The NOTE 2 is a slightly upgraded NOTE.

-Slightly better OS
-Slightly faster SoC (32nm, Quadcore, 2GB RAM)
-Slightly more polished (fatter S PEN, new S-Features, microSD above battery, Notifications light, slightly better camera, better screen).
All-in-all, its not a device worthy to upgrade from the NOTE 1.

If you don't have a NOTE 1, by all means go for it.
Android will be very clunky at first (coming from Maemo), but its got full of features and is getting better and better.

The Google ecosystem is also great. The only thing you can regret is price, availability and software upgrades (more than Nokia's support though). You can also chroot Ubuntu and get a fairly featured experience.

The next Android Kernel, version 3.4, will be joining the Mainline Linux kernel.
And there is an effort to port Qt-framework into Android OS. Soon you can dualboot into a (castrated) distro on the same stock kernel, or simply do Terminal and C++ processing from within. So despite the short comings, Android is the future. Sorry MeeGo, Mer, Tizen, Jolla won't be.

PS If you buy a Lumia device, even with WP8, you will regret it deeply. Its a "boxy iOS" with no relation to Maemo or N900, whereas there's some overlap with Android devices.