Is Napster worth paying for?

From a legal standpoint yes it is. If you don't mind the very real possibilty of being taken to court for piracy and sued for a decent amount of money (most cases range from 30,000$-100,000$ as they will consider one downloaded track as the full album price even if it was only one song) then a legal service may not be for you. Paying for a legal service such as Napster also provides more incentive to the artists to create more music.

Seeing how Napster's new subscription levels allow you to stream as much as you want and also give you track credits which can be used to purchase MP3s which do not hold any DRM I don't know why anyone would pick another service. This compares to buying tracks on iTunes but you also get to listen to as much as you want to on the website without having have to pay for those tracks individually. When you find the tracks you want to keep you can use the credits provided to buy them. The prices on this subscription go from 7$ a month with 5 credits up to 60$ a year with 60 credits.