Something I found out when I first got the 722k and the ota tuner module. Do NOT install the ota module till the receiver has taken its first software update. I did the opposite and found the ota sensitivity was really bad. I got all kinds of breakups , pixelation etc. I took the ota tuner out and re installed it and it worked like it was supposed to. Since the last software update the sensitivity of the ota tuner improved and is now comparable to what I got on my 622/722 dvrs. The only thing I notice is that the ota tuner has about a 5 - 6 point difference between them on the same channel in single mode using the pip feature. Now this isn't enough of a difference to cause any break ups and pixelation.
For example in my area of Southeast, Texas:
ota tuner1/tuner 2
76/71 on ABC & Nbc - 12.1/12.2
88/83 on CBS & Cw- 6.1/6.2
78/73 on FOX- 4.1