Yep, had mine for a day or two now with the Topo map of the UK. To do an in-depth review would get me the sack, but first impressions are:
Good
Build quality is great.
Unit is relatively easy to install and use.
Highly configurable
Extensive training info
On-road navigation is good with listed turns and road names (advantage over OS)
Despite the map quality (see below), defined routes are clear enough to be useful.
Interface with Garmin Connect is simple - GC is looking like a tidy tool, although its still early in its development.
Phone Support is good
Indifferent
Screen is a bit too small compared with satmap.
Displayed map quality is very ordinary when compared with OS - I wouldn't like to use it for off-road or hiking.
Bad
Forget auto-routing unless you want to ride your bike on the M3 - not an issue for me as I like to handcraft routes anyway.
Supporting software (MapSource, driver installation etc) is shocking! Get something like Tracklogs (my fav) or Memorymap if you're serious about creating routes.
Manuals - soft and hard copy are equally useless. Expect to become a regular on garmin forums.
Map installation is a pain (but good support solved this)
Also worth mentioning that I had a scare the first time I charged it. The battery indicator only showed the battery as half charged, despite 12hrs of charging. I did a full discharge, followed by a recharge and this seems to have solved the problem.
If anyone has any specific questions, list 'em here or PM me. No promises at the 'mo, but I'll do my best.