Whether you want to upgrade your existing Note II to the brand new Note 3 is completely up to you, and your pockets. Sure, the Note 3 is one of the fastest phones on the planet now, with a larger screen and all, but, if you don’t care about raw horsepower, you don’t really have any reason to grab the latest phablet, except its new S-Pen features.
Luckily, these have been now ported over to the Note II, in the form of a custom ROM, based on a leaked Note 3 firmware. There are a lot of things working, like Air Command (complete with Pen Window, Screen Writer, Scrapbook and Action Memo), Gallery, Launcher, Safety Assistance, S Note, Sketchbook, S Planner more. There are, of course, some bugs too, which usually come from early builds and porting stuff over cross-device.