I've bought a bunch of MyThemeShop themes in the past, super happy with the designs but never needed to contact support.
Recently I had a bunch of questions, mostly about minor theme tweaks but they were mostly answered within a few hours.
That's impressive considering some theme companies can take a week to answer one, then respond with "yeah that sounds like customization so we can't help".
MyThemeShop's support is impressive, couple that with the great theme designs - it's an awesome experience all round.