I use Wordpress with the ascend theme, because the site covers content other than just my comics.
For the comics part, I use a webcomic plugin that is integrated with the theme. It doesn’t work smoothly with all theme, so I had to do some fixes for an older theme, but now with ascend it’s working like a charm. I also made some flip books for my previous work. It’s a really neat option for graphic novel, and look good on tablet, but it’s gadgety.
Actually, I was considering getting rid of webcomics plugin, and just use elaborate galleries to display my comics, but I haven’t found time to really investigate this option.
We also have an online shop using woocommerce and newsletters, but not really for my comics.
I generally back up once a week, and always wait some time before updating system and various plugin, so I never had major issues so far.
SEO, spam and back links are a pain and time consuming, and I’m very bad in design, so now I keep things simple, and the theme does it’s magic to create responsive results for various devices (but still need to double check the result before posting). I also had trouble with https at the beginning, but now everything is sorted and secure.
Cost side, only domain name and hosting through host gator. Service so so, not very fast, but it’s cheap...
In conclusion, if it was only for comics, I’d probably not bother and just use Tapas or comics fury, it’s good enough to have a good base...