Yea, they are wonderful for pratice. I have used one for about 3 years now and it is great. The new model(PX4D) can be used for guitar or bass. Just make sure that you invest in some good rechargeable batteries and don't use to wireless headphones, they suck balls!
http://launch.groups.yahoo.com/group/Pandora-PX4/I moderate here. (Just watch what you post, the other guys are watching!)