One advantage of the 612: no need to have it hooked up to a phone/broadband connection. Both can take external hard drives so storage advantage of 722k is somewhat negated.
Another one for 612. Counts as just one tuner in the 4 max lease quotient. I love my 722's, but have never used PIP. Just record and watch full screen.
I'm glad you have six tuners, but the official line is 4. Some can get by with more, some can't.I have 6 leased tuners 622/722/722k and I just added an owned 612 for my daughters room. She doesn't need PIP, so my only issue is I am having a problem with one of my local OTA channels dropping out, it doesn't happen on the others so I assume the 612 OTA tuner is not as good as the others tuner.
I'm glad you have six tuners, but the official line is 4. Some can get by with more, some can't.