You can navigate while playing a song without interruption, keyboard shortcuts make sense, I can even play from Emacs!
The only thing I regret is the buggy login via facebook (the logo doesn't show, or clicking it doesn't do anything).
My biggest peeve with SoundCloud, though, is keeping track of what I have listened to and trying to remember a song that I thought was amazing. I didn't have an account for the first several months I was using it, but I would just remember the Artists I like and listen to their profiles/likes. Not being able to remember songs and artist names motivated me to make an account and start following them, and liking the songs I wanted to hear again, reblogging the ones I want to share with others... In the end, even though it was frustrating for me, I suppose this is good for SoundCloud and getting people to provide feedback.