I work in the public television world, and this is a big deal to us because we get a large percentage of viewers over the air (old, low income, etc).
I can assure you, digital signals are harder to get a picture with than analog. With analog, a little interference means some fuzz. With digital, it means you don't get a picture period.
Indoor antennas are especially affected by the switch which has a lot of stations worried. I can assure you most of our stations are operating at full r near full power and our research is showing it's hard for a lot of viewers to tune in.