Hmm, I'm on the fence. I have a Nook Color that is rooted and I also run CM7 on a mSD card. It works great for the most part, sometimes it lags though and sometimes I have random reboots. This is on a Sandisk class 4 mSD card.
I just got a 32gb Sony class 10 mSD card and put CM10.1 beta on it. That definitely runs faster but it I'm getting reboot issues with it as well (could be the beta).
I'm wondering how much better the Nook Tablet performs over the Nook Color. Streaming video from Neflix and HBOGo can lag a bit on the Color although it is usable.
If I picked one of these up I'd give the Color to my girlfriend.