i'm garmin all the way, got a nuivi 610 and my bro hase anothe rone the same cant remember the model but its got the same feturs but a smaller screen, they are great, and my nuivi actually gets a signal through the windscreen unlike the i3 i had, my dad has a TT that i got him but idont like it.
a tip though garmins have a quirk where they don't discriminate very well between farm roads and b roads, so they can send you down a ranther bumpy route, set the vehicle to bus or lorry and it stops all that.