Get seat time in several boats if possible, even if it's just on the sales floor. If you have a demo day close by that would the most ideal.
Until you've put the time in on the water, you can't really say. I've been in a quite a few SUPs, fishing and not. I actually fished from one before they were marketed as fishing vessels. They aren't an ideal choice for most waters that are accessed by motor boats. If you're accessing backwaters or mother shipping, they might be the ideal vehicle. I don't know of ANY actual rollovers with sit on top kayaks. I would fall off my Compass before rolling it, and reentry is not difficult at all. I'd say the hardest reentry was with my Commander, but that was a hybrid kayak/pack canoe design. While strongly urge EVERYONE to practice reentry, falling out is such a rare occurrence. I only know of two people in my circle that done it in the past two decades.