The thing with the whole pick up artist culture is that many of the guys were former nerds with very little success with women (in fact, in Roissy's posts, he sometimes makes brief and obscure references to Dune, Lord of the Rings, Star Wars, sci-fi nerd type stuff). So, when they finally learned "game", and started attracting women, they tend to take their aggression over their previous failures out on them, via "pumping-and-dumping" and aggressive posts online about it.
I think PUA's have some very good ideas and advice, especially in regards to building up self-esteem ("inner game" they call it), not appearing needy, and creating attraction via flirting. As someone who suffered with low self-esteem most of his life, reading this stuff (and also going to the gym, getting LASIK, getting some new clothes) has helped me a whole ton. As someone who wanted to know WHY women say one thing but want something else, game and to a lesser extent, evopsych, helped clear some stuff up. I went from being extremely passive and wishy-washy, to the only person in my group who isn't afraid to approach girls at a bar, to someone who isn't afraid to tell a girl "no" or stick up for myself. I went from someone who went "I dunno what to do, what do you wanna do?", to someone who picks the date spots. From someone who was afraid to even touch a girl, to someone who usually gets makeouts by the second date. From someone that sought female approval, to someone that isn't afraid to challenge a woman. Since the start of the year, it is rare that I'm not either dating, or in a relationship. Last year I couldn't even get a follow-up date with most girls I dated. Now, I got a 3rd date with a cute redhead on Saturday even

But of course there are negatives. I would hate to fall into a trap where I get so good at meeting and banging women, that I start to see them as all the same and objectify them (an important theme of "The Game", by Neil Strauss, the book that started the whole PUA movement).