I own both a V1 and an Escort 8500... I use both regularly.
I agree that the V1 is probably the one I'd own if I only had one. The arrows are incredibly useful. But I find it to be a terribly annoying radar detector while driving in town. Even my wife hates how chatty it is and in the end I end up turning it off becuase its so obnoxious. However, when I'm driving agressively its clearly the best unit to own.
On the other hand, I find the 8500 to be just as sensitive... and although its missing the arrows, I think that its comfort features like auto-mute and such make it much more civilzed to use while driving around town and in traffic. And those times I'm speeding just a tad over the limit, its nice to get a few chirps to get me to slow down.
So - for me... I take the V1 when I'm driving agressively... and the 8500 for every-day-to-day driving.