I just got my Nuvi 3790
The display is super crisp and bright. Even in bright sunlight. I had my Nuvi 1690
I transferred my favorites (waypoints) from the 1690
The unit is super thin. In fact, I almost lost my grip on it a few times it is so thin. I bought the Garmin case for it and it fits very well. Easily fits in my shirt pocket.
I did a backup on the hard drive, which by the way is a whopping 8 GB, using a little over 4 GB -- room for expansion indeed. I couldn't select all on my mac and get them all to copy over, but I burned a DVD and pretty much everything was copied from what I could tell. It took about 25 minutes or so.
The unit did get pretty warm in use, perhaps because of the black back and the sun. I haven't used it at night to tell if that is it.
I live in northern Virginia and was not able to pick up traffic. My 1690 was showing traffic in the same areas. The 1690 is cell-connected, the 3790
In comparison with the 1690 with most detail selected, the 3790
I do like the ability to rotate the screen. I didn't think I would but I like the portrait view. It gives me more of where I am going rather off to the sides. i will need to experiment with it.
Routing is a bit different than my 1690. I will see how it evolves in its learning my routes. Calculation seems quick. It did take a while to lock in after being powered off, but nothing appreciable.
I can easily pack this, or put it in my shirt pocket and take it most places.
A great GPS. Pricey, but wonderful. This is the iPhone 4 of the GPS world. Nothing comes close to the beauty of the 3790