Somebody somewhere sometime tested these DVR's and knows exactly how fast they are.
Having owned an HR22-100 from DirecTV, I can tell you some of that. At one point the HR24 was the gold standard for a fast responsive DVR from DirecTV, but no longer. The issue is that *some* DirecTV DVRs are fairly responsive, while others with the same firmware and hardware are not, and nobody seems to know why. I waited two years for them to fix mine, and there was always the promise that the next firmware update would fix it (and firmware updates took six months or longer.) From turning on the (always on) unit to being able to select a program and start playback, the average time was 22 seconds. At random times, I could press a button seven or eight times before the DVR would respond to one button press. 30-second skip took about 2 seconds.
The issue of stopwatching is that it is highly unit dependent. How much space is left on your hard drive? How many tuners are doing something right now? How fragmented is the hard drive? When I first got my Hopper, it was blazing fast. As the hard drive has filled up, it's no longer quite so fast, but it is still very quick. I never have to push a button twice to get it to do something.
There aren't hard and fast numbers, but side-by-side comparisons have always shown the Dish DVRs to be faster. Sometimes a lot faster, sometimes just a little. But you're getting a slower DVR that can't do some of the things Dish's can, so I hope you're happy while you go through your 24-month waiting period.