I've got two NC and a single NT in the family. The NC is definitely more hackable. Solutions are coming for the NT, but there's nowhere near the selection yet. The NC is also almost unbrickable. It's a great device to make mistakes on.
Performance is very good. I won't say "buttery smooth" because things are definitely faster on the NT. Even browsing seems to benefit greatly from the dual cores. However, with my NC overclocked to 1.2 GHz, Netflix and video are perfectly watchable. Battery life is also pretty good, better than any other device I own.
I'm running B&N 1.4.1 rooted because I want the B&N content, but I would suggest CM 7.2 RC0 Mirage if you don't care about B&N stuff. ICS is also nearly viable for day-to-day use (depending on your day, of course.)
Bluetooth is hit-and-miss depending on what you want to do. I've read of people having success with BT keyboards and GPS, but I've only tried the latter myself. It worked well enough that I could have a GPS receiver up on the dash, but I haven't done much actual field testing with it. BT audio is definitely out on the NC, and from what I've read, the NT as well.
The NT does provide a mic, so that might be important.
I considered upgrading to the NT, but now I'm waiting for the $250 quad-core devices that are supposed to hit this year, so I'm keeping my NC and trying hard to save my money. At $180, the NC is a decent deal, but you might find refurbs for even less with a bit of looking. I'd suggest a NC.