What Awesome_Elvis said.
FWIW I was using the 6i6 1st gen for a long time, and I recently switched to an Apollo Twin after it died - Even going through the Apollo XLR channels rather than SPDIF, it still sounds a lot better. It's like someone took a blanket off the speakers.
Awesome! ive been looking into the Apollo Twin...just a bit scared at the price hahaha heard amazing things its certainly something i will be looking into tho \m/