Yeah, it could really do with a volume slider. Fast-forward/back/next/previous track would be great. At the moment if you click another track in the playlist it clears the playlist and gives you a new one.
Some of the tracks aren't complete - and just stop half-way through.
They've got plenty of hits, but even in 'discovery' mode their library really doesn't go very far from the well-beaten track.
Their online-payment/login system sucks too. I'll forgive the Franglais instructions, but rather than a normal login - you just get a random 8 character access code. Oh, and it doesn't save your login or preferences either.
So, far from great - but for ?2 for a month of easy listening - I think I got a pretty good deal.