Not professional services, but a "regular" Canon service story:
Canon 500mm seemed to have less snappy AF than I was used to. Fearing repair time might push me past the Tyndall show, I overnighted the lens to Canon NJ. They got it Thursday, diagnosed it Friday and fixed it today, Saturday. I'll have it back after only one week to include shipping time. Nice!
Of course, it would have been nicer if the lens hadn't broken in the first place (to the tune of $385), but for a precision instrument, I do bang it around a lot, so I'll live.