i have been with direct only a few days - so far there are things i like about my HR-21 .. and only a couple of things that i guess could be a "negative" for those that need the features.
Hardware wise .. 722 and 622 have the edge with the three recordings at a time - over the air tuner and TV2 output .. however in my opinion the software for Directv's receivers is streets ahead of the 622 that I had for the past 18 months.
As i only have a one room setup - and as the OTA add-on for the HR-21 is only a couple of weeks away from being a reality - for me at least - the Directv receiver is a much "better" fit.
I like the on-demand stuff, - i like the media player software - I prefer the guide navigation and layout (jump to a date/time feature is nice) the channel switch is a little slower than the 622 - but overall .. for my use at least ... the HR-21 is the better bit of kit.
(p.s. my wife prefers it too - and that's worth a LOT for those of us that have been married a while )
Now - if we could get the HR-21 body (looks prettier) with the Dish network hardware features and the Directv software ... we'd all have to find something else to disagree about.