The real story is this...
Photopost is by far the better gallery software on the net period.
You'll notice alot of features on photopost get copied by it's competition (who ever that may be)
currently supports about 17 forum integrations, works on RC3 like a dream (styles, comments, avatars etc) lots of pre-installed styles, can work as a stand alone gallery (who needs a forum???)

and has more features than you can shake a stick at... support is professional fast IMO, support staff actively help you by fixing errors, custom work, setups etc...
VBaG is good, but started as a hack really and feels like a vB hack, if you want the pro stuff you gotta go for PP really, you can make an entire site from the software itself if you wish, no need to own a forum, but i would say that if you own a vbulletin and can set that up ok, then to compliment it perfectly you must get PP, it's the discerning choice for the webwise!
The only thing missing in photopost (and this is why there's a myth surrounding it's popularity vs vbadvanced gallery) is simply this, it's the phrase > "vBphotopost" add that little 'vb' at the begging of a hack name or whatever you'll have a winner regardless if it's crap or not!
-b6