Those familiar with only one product line aren't much qualified to make comparative judgements.
But they can make observations about what they're using, which doesn't seem to be your case here.
Are there "faster" DVRs out there?
I question someone saying theirs tunes in < 500 ms, but that's because my own TV can't do that from an OTA antenna.
I haven't channel surfed since cable added a guide some 20 years ago. I surf the guide.
I've seen the dish video scrolling through their guide and would be hard pressed to see a difference from my own HMC/Genie speed. Maybe a high speed camera could show a difference but if it's faster than I can read, what's the point of being faster?
Do I wait a moment for my guide to come up?
Sure, but it's truly only a moment, and so short it's hard to quantify. I doubt I'd get past "one" of a count.
Does the DVR take longer to tune to a channel than my TV?
Yep, by about 1 sec. It's slower when it changes resolutions, but this is an option I select, and I can turn it off if it was a problem.
With U-Verse I didn't have the option, and since I watch three or four resolutions, I'd rather have the option than not.
So I guess I do have more experience than with "one product".