Mileage rocks. We bought it last week and immediately took it on a road trip. Got 300 miles on a little more than half a tank. Handles well, pretty comfy-- (I'm spoiled by the old Lexus I had before). Bells and whistles that come with the tech package are pretty cool. I rented a Prius for a few days awhile back and the Altima ride is far (far!) superior. Better kick, more comfort, and better than average looks.
Bluetooth wireless phone, dual heat for passenger and driver. Nav system. Gratifying little display screens that tell me how much gas I'm using/saving. Extra entertainment value offered by car sensors that know my key/fob is nearby.
No flat interior surfaces to place phone or iPod. While there are THREE cupholders, remaining interior storage for empty mugs, combs, small toys, spare keys and other detritus is harder to access. You also need a master's degree to operate nav's more sophisticated features.