Unfortunately, there's nothing too terribly exciting at this one to get you excited.
Party Females fits the bill in terms of niche at least. There are girls in bikinis, getting hammered, showing off their tits and asses, and generally whooping it up for the guys with cameras. Plus, you get access to quite a few bonus sites as well. But that's really the only halfway decent stuff going on here, and I don't think those are enough in the long run. The quality, though in HD, is probably a bit behind the times. The site itself is pretty plain in terms of navigation and all. Plus, the site isn't huge, and it doesn't seem as though the site grows ever. All in all, I just don't see a huge reason to join this one over the other similar party sites out there that might be larger and more active.