I received my AirTV adapter on Monday, but couldn't install it until today (Saturday). While replacing the old one, I noticed that (1) the old one was pretty hot and (2) there was a 3-way splitter in the circuit for no reason. So, this wasn't exactly a good comparison. But upon rescan I got 65 channels including Washington D.C. locals all of which come in around 100, and Baltimore stations which come in around 85-90. This should fix my WMPT channel 22 breakup problem, which was the whole reason for my big antenna on the roof and this new more sensitive tuner. All distribution amps are out of the signal path as well.
I also got some stations I don't remember ever seeing before, which have fair (70's) signal strength. I'll have to look them up but I'm suspicious I'm getting Frederick stations as well.