My concern about the Garmin Nuvi series units is that they apparently contain a non-user-replaceable lithium-ion battery. Lithium-ion batteries begin deteriorating as soon as they're manufactured and have a lifespan of 2-3 years even if they've never been used/abused. To replace the battery, you have to send the unit back to Garmin who currently charges a $250 fee to do it.
So what, right? If you only use your Nuvi in a vehicle, seems like a dead battery shouldn't matter. Here's the problem: I recall reading a report over at gpspassion.com of a guy who's Nuvi wouldn't work when the battery was drained even if he plugged it into the car (he had to wait until the battery recharged before it would work). I don't know if anybody else has duplicated this problem but IF it's true it means you'll have problems 2-3 years down the road even if you never use your Nuvi away from your car...
Shame because it's otherwise a kickass line of GPS units. I'd been tempted by the Nuvi 360 myself...