I just got one from play-asia. It is awesome. fully compatible with ps1/2/3 games, charge lasts just as long as sixaxis, and the vibration is very powerful. (i tried other wireless controllers, and they vibration was too light.)
It is so worth the extra 20 bucks, if only to have one now, avoid the lines, etc. I know it is a bit expensive, but it is great. (also, no disconnects, as happened with certain games using the radio shack usb adapter and ps2 controllers.)
It is worth noting the radio shack usb adapter does work pretty well for ps2 games, with only a couple having disconnect issues after about 2 hours, on certain games. it worked great with movies, etc, with full vibration on ps3 games. No support on ps1 games, nor ps3 games, so the dual shock 3 is definitely worth it, but do not regret getting the usb adapter at all.