I played around with a friend's Dash tonight and it wasn't as bad a device as I thought. For a smartphone with kind of a funky body I wouldn't kick it out of bed...
As a WM5 user I tend to look down on smartphone edition (phone elitism ftl) but it was a pretty useful little device.
I really like it too, I just eventually found that the keyboard was a little too awkward for me. Ditto the volume strip.
We have an HTC S620 here in the office - which is the same thing without the T-Mo cruft. It's very pleasant to use.
And this might just be me, but it feels a touch faster than other standard edition phones out there. Maybe it's just that i'm comparing it to the leaked and buggy wm6 ROM on my blackjack.