I've been noticing a trend when using my phone for music at work. Sites like Bandcamp have an excellent mobile site that is simple and intuitive. However, once I find a cool group on Bandcamp I end up switching to Spotify. As nice as the mobile website is, it still takes a long time to switch between albums or artist pages. 3G is no speed demon but it's where the mobile web is right now and will be for the next year or two.
My question: is a semi-confusing OS app (i.e. Spotify) that is snappy and responsive better than a very usable mobile website? That is to say, is speed heads and tails more important than any other mobile application usability factor?