N-triq over Wacom kills the Pro 3 for me.

I haven't read through the seven pages of this thread, but given how dissatisfied that I am with the Wacom on my SP2, no way would I say that N-Trig kills the SP3 for me, especially without trying it out first. I almost never use my pen, because no matter what I do, it doesn't calibrate correctly, and I've tried a bunch of things, including the Surface toolkit, or whatever it is called, for calibration. It's ok on most of the screen, but at the edges, forget it. I'm not giving Wacom my loyalty after this, and this being my first Wacom product, I'd say that they've made a pretty bad first impression.
 
As for compatibility:
N-Trig closing Wintab compatibility gap — Surface Pro Artist

N-Trig engineers enlisted my aid in better understanding the issues confronting them. Within 24 hours of our initial contact, I was given exclusive access to a new driver test build.
[...]
Indeed, isolated issues remain to be sorted out, but I can now report that the vast majority of Wintab software that I've tested now recognizes pen pressure on the Surface Pro 3. Additionally, I tested the new drivers on the Sony Flip 15A and Acer Aspire R7-572 and both have yielded similarly positive results.
[...]
ZBrush? Check. Painter? Krita? Check. Check. Mischief? SAI? MyPaint? Check. Check. Check.

Notable exceptions include the ever problematic Autodesk Mudbox, which still doesn't recognize the pen and Adobe Illustrator, CorelDraw and CorelPhoto-Paint which all exhibit intermittent pen issues.

The N-Trig developers tell me that they're noticing other more subtle issues in some software which they're attempting to address before the Surface Pro 3 is released June 20.
 
I am a digital artist for more than 13 years who is really loving my SP3. I also own a Cintiq for 6+ years now. SP3 pen just feels great to draw and paint, more than SP1. It is something you definitely have to try out yourself. Don't let any internet debate with technicality discourage you from experiencing it first hand. Make sure to try sketching with OneNote, I was shocked how fluid it is this time compare with SP1. I am using it often as my Togo sketchbook. WACOM Paper and Autodesk Sketchbook are also great apps to try.