Honeycomb on the Tab is not worth bothering with. It's more like alpha. Same is probably true on the Nook. Without the Honeycomb source code there's not much they can do.
Most of the development on the Tab is for the GSM version. You gotta be extra careful what you flash on the CDMA Tab as most of the hacks are for GSM. But of what I've seen, there's not a whole lot of development going on with the Galaxy Tab. If you like to tinker and hack, Nook is the better option. But Tab comes with most of the stuff built in so there's less of a need to hack to enable functionality.
Battery life is not great like the bigger 10 inch tablets since the battery is smaller. Figure about 6-7 hours of continuous use. So if you use it on and off, it should easily last you two days.