I have trying to use Doubletwist since it uses the information from itunes. I use iTunes ans I like it. But it sucks when trying to put music on the droid from an itunes based library along with use the playlists.
In windows it is ok but it takes so freaking long to update its DB with the changes you made in itunes and to your playlists. Forget a quick sync if you want to do that.
I tried Mediamonkey and as powerful as it seems I really really despise the interface. Why not something simple like itunes? I mean I dont care about location or anything like that. Maybe I did not spend enough time with it but the UI just really turns me off from using it. Plus I dont see me going away from iTunes just cause of the droid. I am hoping goggle will make a addon or something like blackberry did with their mediasync. Let iTunes do what it does best and just sync what I tell you from it.