n-Trig pens give 256 levels of pressure (not 1024) but if you can tell the difference you're a better man than me.
n-Trig pens are metal, nicely weighted by the battery, and feel much better than the light, cheap, plastic Wacom pens.
n-Trig pens only use the battery when they are actually in use, so battery life is long, at least a year.
AAAA batteries are unusual but not difficult to get hold of. Next day delivery from most places.
Surface Pro 3 Pens use Bluetooth only for the purple OneNote button. Pairing is simple, fast and reliable. All other pen functions are provided by the n-Trig digitiser.