I work at a game publisher, so we've had the Vita for a while now. Finally got my hands on it for a few hours yesterday (people are practically fighting over it) so I've jotted down my thoughts here:

I'm reminded of the Samsung Galaxy Nexus, big slab of a smartphone that it is (though this is much larger).

Specifically, I spent some time playing with the UI and functions, then jumped into Blazblue and a couple other Japanese titles. The new display is VERY high resolution and performance-wise hardware does appear to live up to what was shown at past conferences.

The placement of the face buttons is a little too close to the analog sticks, and I found my thumb covering the speakers very often, unfortunately.

Mine had wi-fi enabled, but unfortunately I didn't have a chance to test any online features.