I use sai all the time and I love it but I mostly use it to make fun paintings and such I actually draw most of my comics by hand because proportions are hard for me to do with a tablet. /=
It's got a realyl nice painterly feel if you like to color things and I think the water color tool is amazing. I say it's totes worth trying
I use sai for my entire comic making process, and I'll say straight up that if you think it's limited it's because you never learned how to actually draw. The program has amazing brushes, all the tools you could possibly need (except a text tool I'll give you that), and you can create anything from super simple cartoons to hyper realism with it if you just, well, know how to actually draw.
It does have an equivalent of a burn and dodge layer (shade and luminosity) (also I was pretty sure burn and dodge had been confirmed for bad tools because they just don't look good but I guess whatever floats your boat), if you can learn how to draw a simple circle dialogue bubbles aren't a problem, and getting good blending really isn't hard as you can adjust the setting to make any of the brushes a blending tool. (You can even create and add your own brushes if you look up a simple tutorial) It creates some of the smoothest lineart there is, too, so I'm honestly not sure what you guys are going on about with it not being good for lines. Heck it even has one of the best stabilizers I've ever seen.
I will also say that you should buy the legal version. It really is not expensive, and it's a great program that deserves support.
Uh, no, I know how to draw, and I think SAI is limited because a.) it lacks a text tool and certain shape tools (there is no circle tool, and unless you are da Vinci and you can draw a perfect circle freehanded, then a circle tool is a nice thing to have), b.) it lacks many of the layer and blending modes available in, say, Manga Studio/Clip Studio Paint and c.) There are no perspective rulers, which are immensely helpful, and while I know it's perfectly possible to draw good perspectives without those tools, they are extremely useful tools if you can get them, and d.) its magic wand tool is not the greatest.
A better, larger program won't teach you how to draw, that's true - but SAI is lightweight, especially if you're going to draw comics. And I say this as someone who has completed professional illustration jobs using only SAI, because that's what was available to me at the time.
I will give you that it does amazing lines, especially compared to Photoshop - but compare it to Manga Studio/Clip Studio, and it comes up kind of short.
Since everyone has already posted about how awesome SAI is, all I can is - SAI is love, SAI is life.
I straight up admitted that the lack of a text tool was its one real shortcoming, and I agree that at least is a problem, but the rest of this is goofy, haha.
a.) Shape tools are something that really shouldn't even be used in the first place due to the generally artificial and out of place look they give, but there are multiple methods to drawing a perfect circle or a square in sai that honestly aren't difficult at all. Specifically the method of simply dropping a dot and erasing the inside, and using the curve tool both work well. Heck, I even found a third way looking for links to these examples, haha.
b.) After looking up the layer options in Manga Studio and Clip Studio Paint I'll straight up say they're unnecessarily complex, and you can get the same exact effects in Sai just using different methods and tools. Sure they might be nice if you're feeling lazy, but they aren't by any means offering you anything you couldn't achieve just using sai.
c.) Perspective lines take all of about two seconds to sketch out. Sai has a means of making lines with literally ever brush it has, and once you get right down to it all perspective is is a dot or two or three with a bunch of lines coming out of it. :/
d.) The magic wand tool is so adjustable you really can get it to do just about anything you want. You just have to take two seconds to actually look at the settings and adjust them to whatever it is you're doing.
Like, I'm not trying to start an argument or anything, I guess my point is that sai, while simple, works perfectly well for drawing and comic making. The additional tools found in other programs are just a lazy way of doing the exact same thing you can do in Sai, and, again, if you understand how to draw in the first place you probably won't need most of those tools. It's always astounding to me how many people act like a program not doing everything for them means it's somehow lacking in something, lmao.
Its not just being able to do it, its also about efficiency. Perspective lines don't take two seconds, maybe if you're draw 2 objects or don't draw backgrounds. Oh and by the way this statement you wrote sounds like an argument. Its sounds kind of degrading. Sai's purpose is to be light weight and limited and easy on the user. "this software make digital art more enjoyable and comfortable" is a quote directly from their website. While Clip Studio Paint/Manga Studio's purpose is to make creating comics efficient and fast without costing as much. Just check out their front page. Even pros have trouble with perspective and difficult angles. http://www.clipstudio.net/en1.
Like @AnnaLandin said
And by your logic the lack of a text tool isn't a real short coming because their are multiple methods to add text in sai that aren't difficult at all. All you need is a free word processor and print screen. You're comment sounds a little to high and mighty.
I was going to say the same thing, it's not about laziness, it's about efficiency. And the more efficient the program you use is, the more comics you'll have time to make. If anything, we're all lazy for using any kind of digital drawing tool, compared to those who draw traditionally, right? 
I know how to draw in perspective, but it's really time-consuming, and so I get bored, and so I often choose to draw things in a way that I won't have to worry too much about perspective. I use Photoshop now, and that will always be my preferred drawing tool, but I am seriously considering buying Clip Studio Paint or Manga Studio just for the sake of getting more help with the perspective drawing - it would save me SO MUCH TIME.
I admit I haven't used much of SAI, but I highly recommend trying out OpenCanvas 6. There's a 120 day trial period. It DOES have a text tool and the program is pretty simple to figure out.
If you use Sai for the drawing itself, and then Photoshop or another editor of your choice, I doubt that you'll need anything else.
I tended to add colour with Photoshop, but I've recently tried doing it in Sai and I like the results.
I liked Sai, but (especialy for comics) I LOVE Manga Studio. ALSO, it's normaly about 50$ but is on sale (sale ends today) for 15$
15$ is not much for such an amazing and powerful tool.
You assume that everyone works with the same methods you do, and with the same advantages. There are artists out there who struggle with shaky hands, or who suffer from astigmatism, just to name a few - and the latter tends to mess up their ability to see what they're doing wrong when they're drawing perspective. Having tools to help with that is super-useful - and for people like them, SAI is limited. And before you say that they don't matter - more people struggle with these problems than you might think.
Also, this is a forum for a comics-website. Most people here are looking to make comics. For them, using Manga Studio/Clip Studio instead of SAI makes sense because where SAI is your average drawing tool, MS/CS is geared specifically towards making comics, and contains convenient tools for making panels, speechbubbles, text, etc., etc. I'm not saying you can't make comics with SAI; I'm just saying that there are programs that make it easier.
Sure, you can work around SAI's lack of a text-tool. But I've found it more convenient to be able to do everything in the same program; that way, changes are easier to make, and the final result looks nicer. Why go for a program that doesn't have a native text-tool when you can go for one that does?
As for if I'm being high and mighty - you can be the judge of that, but I'd like to point out that it's not that I don't like SAI. I use SAI daily, and I fully acknowledge it's a good program for drawing. I just thing MS/CS is better when it comes to making comics.
shaky hands
SAI has a stabilizer.
Same advantages
Good artist privilege. Making people who suck at art look bad. How dare you.
make it easier
i.e. cheating
Yes it does - but it doesn't have a line-tool like Photoshop or Manga Studio does, which is useful to have while inking architecture. Like I said, I'm not saying SAI is bad. I'm just saying Manga Studio has some advantages, tool-wise, that SAI doesn't.
I'm not talking about people who lack artistic skill. I'm talking about people who have very real, physical limitations. There are professional comic artists who struggle with things like astigmatism. To just name one random example; Peter Bergting, who is currently drawing Mike Mignola's Baltimore, has said Manga Studio helps counter his astigmatism (or astigmatism-like problems). And that guy has no problems with artistic skill.
Not to mention the fact that there are people who want to draw comics at a higher pace, and Manga Studio-tools help speed up the process. Being able to, in a quick and easy way, create panels, speechbubbles, text, and draw complicated perspectives with tools native to the program you're using, is a distinct advantage to making do without them.
Is using a ruler when drawing traditionally cheating too? Perspective tools don't draw for you. They just make it easier to keep track of your guidelines, and help cut down on the time you spend staring at your sketch, wondering if it's correct or if you've messed up somewhere.
There is no badge you get for drawing every line of your perspective-sketch freehand. It is an admirable skill to have, certainly, and I wish I was better at it than I am, but it does not make you morally superior to people who need a bit of help in getting it right.
