Quick update:
The unit is a great package. Everything you need. It literally took less than 5 minutes to get up and running in the PC World car park.
In short, the unit and mount go very nicely just about anywhere. Battery looks good for about 7-8 hours, however you can use the supplied cigarette lighter cable.
GPS reception in Central London is a little sketchy, but still ok to get you around. The ASN direction sensor allows navigation through tunnels - updates the map nicely.
Software is very easy to use. Comes with a 128mb SD card, but to hold GB and Marjor Roads of Europe 256MB or more is required. PC software doesn't really do anything interesting. Customisable POI support (speed camera database) is being tested by a few people in the UK right now, and is apparently working very well although the guy I spoke to is under an NDA, so cannot say too much.
Money well spent. Only issue is figerprints on the screen, although a screen protector ought to fix that.