Well, I'm going with vB4 since vB3 doesn't seem very up-to-snuff with recent changes in how the worldwide web functions, and is essentially apt to break at some point or another. Places like PC can stay afloat since they have administrators who also work as engineers for the place, so there's no hint of them falling ever.
Speaking of which I'm in the process of exporting the database from my localhost right now!
That's just a crying shame. A while back in 2012 I ran a vB4 forum called PokéSphere, and it got DMCA'd, and was just never the same with MyBB. Right now I'm trying to bring it back with some offshore hosting and am tossing around my decision of whether to go with vB3 for user comfortability or vB4 for compatibility.
I just don't know what it was about the forum but I really liked it and felt incredibly at home. Sad to see it go for good :/
The owner couldn't really keep up with it, irl issues and all, and wasen't feeling it. There was some talk about a new entry in the long listed series, though he's not that interested in Pokemon anymore. And when trying to give ownership to some one else, that didn't end well.