I already told you my opinion directly, obviously, but I figured I'd place it here.
While I may not know too much about twitch these days, since I never really touched it. It is nice, because it has a much larger audience, though as stated earlier, people do tend to hop in and out a lot.
Picarto in my experience is more designed toward artists. It advertises your streams for you, allows you to change your stream name and tags mid stream, and you can multi stream with up to 4 people at once if you pay premium.Plus you can do NSFW streams, which I know personally, some of your work would fall into. I've personally never had a problem with it lagging tbh, and have actually had more issues with Twitch on that. Lagging must very on devices and internet connection.
As far as saving your streams, I never cared to save them on Picarto or Twitch, but you can always have OBS save your stream as you do it.