I skated in my new 12Ks for the first time this morning. Coming from my Bauer One60s which were too wide and half a size too large the overall fit was much snugger and more secure. I was pleasantly surpirsed that the more secure fit translated into being able to feel and control my outside edges significantly better than the Bauer's. My stops and crossovers (both backward and forward) where much better.
The 12K's boot is no where near as stiff as the One60's, which took a bit to get used to, but I feel like after an hour on the ice I had no issues.
The width in the 12Ks is a little snug, but after trying on the Reeboks, as well as the full range of Bauer models (Supreme, Vapor, Flexlite) anything in an E width just feels much too wide, while a D width feels just a big snug. Given the choice, and my experience with the wider skates for almost a year, I'm going to stick with the D width.
I have the yellow Superfeet inserts from my old Bauer's which I haven't put into the 12Ks yet, but I became a big fan of the Superfeet over the last couple of months, so that's next.
Overall I'm pleased with the new skates, they are more comfortable, and it seems like the better fit is going to help my skating.