I've had my 721 for almost a week now and I love it! I had a 7200 for a couple of years before that so that is where my dish receiver and PVR experience comes from. So here's my list:
Items I love!:
- the ability to watch a show and tape another at the same time
- the ability to tape two shows back to back, giving them both the 1-3 min buffers before and after
- the ability to save searches and rerun them from the search history list
- it is MUCH faster in the guide! Moving around in the guide is fast and easy
- there is a ton of harddrive space, I'll never use it all.
- it is very stable and solid
- the UHF remote is very cool. works through walls. features are nice
- many others that I am forgetting to mention
Items that I don't like and wish were fixed:
- When you watch a show that is taping (maybe 15 minutes behind Live or something) and the show stops taping because it hit the end, you are thrown into live TV and you have to go back into the PVR section and fast forward back to where you were in the show
- There is no way to organize your shows in the PVR recorded section. I'd love to separate my Sci-Fi shows (Stargate, etc.) from my wife's shows (Trading Spaces, Cooking shows, etc.)

- The timers show up in the list without the name of the program. Just "123 USA, 7:00PM Friday" or whatever.
All of the bads are easily fixable and I hope they are fixed soon. The good widely outweigh the bads, though.
Overall, I am very happy with my 721 so far!
Steve