I've been to Moss Alley twice since my recent move to Seattle. Their prices seem reasonable (though I'm comparing them to Minneapolis prices, I guess), and they were very easy to deal with. Nice folks - I just got a good vibe from them - and they were very accurate with both their estimate and with the amount of time they'd need my car. I didn't have any major work done (just an oil change, and then a few weeks later they patched a tire that had picked up a nail).