Oh, ah.. I already found out everything from Google and I also still prefer PunBB..
But you don't know what happens later, you've got to stay up-to-date. So yeah, I guess I'm gonna (try) move to FluxBB.
I too did my homework and checked out what I could regarding PunBB and FluxBB. I didn't come up with a clear answer about the "real" difference. I prefer PunBB and plan to stick with it.
One thing that I really like (and FluxBB will probably be the same) is the simplicity and the users ability to change things. I am completely green with PHP and have just started looking at CSS (yes a real amateur ) but even then I can change the theme and alter things. This is great software!
Regarding staying up-to-date, I don't find that so important. I often use older versions of things and have no trouble. I've been using some of my software since the 80s! I like stable. Having regular new releases is the very definition of instability. Still, you do have a point. What is happening with PunBB?