You can't record two OTAs at the same time, but I sometimes run into a situation where three shows are broadcast at the same time (e.g. 8:00pm). Typically for me, at least one of those shows is on one of the main channels (ABC, NBC, CBS, FOX). With the 722, I'm able to accommodate that situation.
Even when two (or three) shows are on the main broadcast channels, the 722 can handle that. It doesn't bother me that only one show would be recorded from the OTA. It does bother me when I completely miss the show because of the two tuner limitation.