(Just throwing in my $.02)
Personally, the next version of phpBB (2.2) is going to be VERY close to vB 2. But... from what i've seen vB 3 is going to have more features that the next phpBB.
As Brandon said, the two influence (sp?) each other. phpBB found a few better ways to do things, and vB will most likely use those ideas in their next releases. However, vB has a team of paid developers to think away about new cool features that they could add. phpBB then takes these new features and adds them into phpBB.
If I had $150 to kill, sure, I'd buy vB. The sole reason is that I'd need to hack it less to get the features i want, because there allready there. (not to say that I wouldn't hack it to begin with)
Jack
and heck... it's all about what you like.
