I like P1 and P2. AVP1 I think is pretty weak. Mostly because I hate how quickly dispatched the predators were. I dont' give a damn if they're "teenage" predators. They still went down like bitches.
Neat toys, though.
AVPR was a step up from AVP, but still fairly weak. The Predalien thing does't do much for me, but it's been around for a while as a concept, so it made sense to see it. At least the Predator in this one was tougher.
I think the biggest problem with the AVP/R films is that they just don't have enough time to do much with the potential tehy have. People recognize this and take them to task for it. You'd think that melding the Predator and Aliens franchises would be untold amounts of awesome, but given the relative brevity of the films (90 min? 2hrs?) and the need to check off certain boxes, pretty much EVERYONE gets underdeveloped and shafted as a result. Predators come off like wusses, aliens seem like mere cannon fodder, humans even moreso. You don't really give a crap about anybody.
Compare that to even the rather 2-dimensional mercs in P1, or some of the cannon-fodder troops in Aliens. Even the cannon fodder in those films were more interesting than those in the AVP/R franchise.
Ultimately, I think that what these franchises really need is more time to develop things. The original AVP comic was, what, a 12 issue series? That's a LOT of time to make characters feel real. Even their 3-issue shorter runs handle characters better. They seem less disposable, and even the disposable ones are more interesting.
You know what the AVP series needs? A TV series on something like Showtime. Somethign that can give it a budget, develop the characters, really make the threat of the aliens and the predators come alive.
Dammit, I wish SyFy wasn't just a joke of a network and didn't have to deal with censors.