I was worried about the D* dvr issue when I recently switched to D* from E*based on what I have read, but really, its not an issue at all. Its not bad at all. There are some differences, the 622 is faster but I work around that instead of using the up and down arrow to navigate the guide, I use the page button and it works great! The HR21 has a screen saver, when you pause a couple of min's it goes to screen saver, my 622 did not. I do like the search feature a little better on the HR21. The remote takes 2 batteries, the 622 remote took 4 I'm pretty sure.
One thing I don't like; and it may just be something I'm doing wrong. But my local CBS affiliate broadcasts a 5am to 6 am showing of local news. Then a 6am to 7 am broadcast of local news. With my 622 I was able to record the 6am to 7am showing mon-fri. The HR21 won't let me. I have to chose record series, so it tapes both everyday. No big deal, I just delete the other but still. It is a difference. Overall. The change was super easy. Dish has one up on Direct for having to only have one cable to the dvr. Direct has to have 2, but not for long.