Pulled the trigger on it.
Not 5 minutes after it was out of the box I had CM10 installed in Hybrid mode. (ROM installs to both internal memory and SD card and boots either rooted stock B&N or CM10). Not that I'll likely ever boot into B&N ever again.
Haven't put it fully through its paces yet, but so far I have no trouble with CM10. It's nice and snappy, so far everything I've tried (games like ShadowGun, Real Racing 3, N4SMW, Netflix, GApps, eReaders, utilities, A/V apps, widgets etc.) runs fine on it.
Text looks excellent on the screen, very nice to read with. Movies (mp4 rips so far) look perfectly fine to me. Side by side comparisons I've seen with the iPad 3/4 show that the iPad res/colors/contrast are of course far better, but on its own the Nook HD+ screen looks excellent to my eyes.
As for the styling, I don't really mind it- the bezels are still the same scale to the original Nook Color/Tablet, but at 9" that makes them seem smaller and the whole device sleeker. The only design element I don't really dig is that stupid open lower corner. Not sure why they didn't just drop that, since the Nook HD does away with it. The SD slot is on the bottom so there's no need for the corner except some B&N marketing guy must think it's a signature look or something.
For me, the size is absolutely perfect. Not too big, not too small. For reading eBooks, the screen size and sharpness could hardly be better. Reading a full magazine page in zoomed out view is just on the borderline of acceptable. Ditto with comics full-page. Still requires quite a bit of zooming around to get a good experience, but nowhere near as much as a 7" tablet.
As for holding it while reading, the size and weight feel perfect- in fact, it feels lighter to me than my 7" Nook Tablet, even though it's roughly 100 grams heavier. It's definitely lighter in proportion to its greater size. The bezels and slightly-rubbery feel to the back make it comfortable to hold.
At first I wasn't crazy about the location of the volume buttons on the top of the device rather than the side, but they actually make a lot of sense when watching content in landscape mode.
I didn't care much for the standard Android keyboard in CM10, but once I installed both Float and Split Tablet, and Thumb Keyboard, I'm able to type very comfortably on it. I'll probably add SwiftKey Tablet on it also and just switch between them.
I'd say it's definitely a tablet worth checking out, the free Simple Touch was just icing on the cake. It looks like the perfect little "take anywhere" device just for grabbing a quick read. For me, since I wanted a B&W eReader and a > 7" tablet, getting both at this level of 'decent' for less than $300 was too good to pass up.