The Nexus has the same resolution - 1280x800 (but a better ppi) compared the Galaxy Note 10.1, and is lighter at 340 grams to boot. Nexus 7 is 5 core (4+1), Note is 4 core.
The main difference - the pressure sensitive S-Pen Stylus plus apps is included with the Note. Oh, the Note has a rear camera....that's a big deal for James Cameron wannabees!
The Nexus 7 will be half the price of the Sammy. And it already has Jelly Bean on board. The only way I would choose the Note over the Nexus is if Sammy upped the screen to 1920x1200, and included a GPS receiver.