Just my 2 cents, but after riding mine a week ago in great powder I am super happy with mine.
I also rode them twice last year and will say the 38" front end will make a nice difference. I will be putting the 38 front end on mine as soon as possible.
I felt like it got up on the snow better then my 11 and the motor/clutching certainly seems much better. Not sure if its the 21/49 gearing, larger secondary, lack of diamond drive, or better mapping, but it just feels stronger.
One thing you will really notice with the Proclimb over the M is it whips around way easier IMO. As in, if your going downhill and want to lay it over and come back up, this is much easier and faster on the Proclimb.
As far as the spindles are concerened, I love them. I run the Powder Pros and really like them. On the 08 and up Ms, they turn so hard it is ridiculous. I absolutely hated the M steering effort. I ran the 05-07 spindles on my 11 and it was way better. The ProClimb steers way easier then the older spindles even. I must of done about 400 pow turns on first ride and my arms and shoulders were not sore. My arms and shoulders were always sore on my Ms. Every ride. I will take the easier steering and less angle all day long!!!