I've had Tivo. I currently have the 622 (which according to the guys on DBStalk shares the same software platform with the 722).
Two TV output is neat. But you need to keep in mind that it's HD on the primary and SD on the secondary. Even more irritating, the only two options for TV2 when watching HD recorded content is 4:3 crop or Letterbox. There's no anamorphic output on TV2, so if the second TV is widescreen you can only see things in the right aspect ratio in cropped 4:3.
Given that, I'd rather have multiple HD DVRs with a network option. It's always irritated me that Dish has Ethernet on several DVRs, but no networking ability.
The other downside to Dish is there's a limit on timers and events. Up until a late this year the limit was about 90 something timers. As more and more networks do the half season scheduling (meaning I'm recording more shows than I was before) the more annoying the limit was. Don't know what the new limit is, but I'm sure I'll hit it eventually.
The plus side is Dish does a very good job with conflict management. It will determine things that are on again in the week and automatically resolve that. It also has a nice visual interface for you to manually resolve the ones that it can't.
At any rate, I think Tivo and Dish spank all the other Cable and Sat DVRs out there. But I just can't say that the Dish is the clear winner. Because it's not. But Tivo isn't light years ahead of Dish like they used to be either.