Couldn't agree more. I don't understand why playing music that's been synced to my mobile has to load for as long as it does. What is happening? And why does my synced collection listing sometimes not load while I'm disconnected from the net? It's mind boggling.
I still love the service, but their apps need a bit of love.
In my experience I believe that the app has to check in every so often for songs to ensure you still are paying for the license to stream it. It shouldn't be doing this every time though.