Just did that friday so I suppose I am the right user for this question. If you get a HR22 you might miss a bit of sharpness but mine seems to have better audio. I am using the optical out. Folsk are reporting that the HR23 seems to be buggy, so for now the 22 might be the better DVR. The 22 is quieter than the 622 and of course black which I like.
One thing I used which the DIRECTV dvr's apparently don't do is navigate a specific number of hours ahead. On the 622 you can be in the guide and hit 24 and the right arrow and it will jump 24 hours. The DIRECTV dvr's just have a +12 and -12 button to jump. The DIRECTV guide is 14 days and dish only had 9 I believe. I do miss the vhf out of the 622 which i used to feed a second tv.
You may also not like the button arrangement on the HR's remote but that is probably a matter of taste. Also, I liked the dish guide having allmost all of the HD together. You may not like the big blue circle in the middle of the DVR that is way too bright but I suppose one can find something to place over that.
Overall the HR22 is a good machine and DIRECTV is a good service. As I have stated elsewhere, I wanted SPEED in HD and Leo Laporte is supposedly near a deal to simulcast some of his web TV output onto channel 101.
Good Luck,
Robert