phpBB - which version?

[yuli]

Not a tech issue (i.e., problem), as regards this BBS, just a tech question in general:
I am not up on the details of the "phpBB story", but i get the impression (strictly a layperson's impression) that many people still use (and prefer to use) phpBB v.2 and not v.3 - could someone with the required insight fill me on on the "why"? Many thanks in advance!