Okay... I have to say, vBulletin 3.6 is pretty nice. From an admin/backend standpoint it has a lot of nice thing (infractions, external data provider caching mechanism [things like RSS feeds], post reporting has some really nice optional stuff that makes it almost like a queue system I wanted, storing of lastpostid statically in user, forum and thread does away with some REALLY ugly queries). From a user's point of view, lots of cool thing there too... multi-quote, lots of usage of AJAX (reputation, marking a forum read, etc.) I like it.
I see you have it running here. Notice any problems at all running the beta on a high usage forum like DP?
I dont like the stock feature either. Not sure if you are aware or not, but there is a plugin that creates a thread in a forum of your choice, rather than emailing all the moderators. Makes it much nicer as once it is addressed, some can just post that the situation is handled.
It seems to use less resources overall. The lastpostid stored in user, forum and thread tables and the external cache (caching of RSS feeds basically) is huge because those are what caused 99% of the crappy queries on the backend. So now they are pretty much eliminated. That's a built-in feature of 3.6.
It sucks that VBGallery stopped working now but that's my fault for not checking the Photopost forums first