I'm using Rhythmbox right now and I have to say it isn't bad. Not great, but not bad. The UI tries very hard to look like iTunes, but it can't hide the fact that the overall works is a bit difficult relatively speaking. Especially annoying are the lack of podcast and radio directories. If I'm going to keep switching (next on the list is Banshee) I need to make a personal page of radio station and podcast sites & feeds to set myself up in the new application.