I had the exact same dillema. Ended up going with the M because of a proven engine and I think its their last year, isnt it?. Poo's Pro seems to be holding up but I reminded myself--Remember the last time you bought a first year production sled--
as sledlift said, try both (or all 4) before you decide, and go with whatever 1 feels more natarul to you. They are all good sleds these days, but I find the steering weird on the artic cats.
Polaris 800 motor is getting great reviews this year and chassis is supposed to be the easiest to throw around. The Arctic Cat has a proven track record.
To buy the m8 sno pro ltd but since we are near the end of the season maybe best to enjoy my 07 summit and get a cat over the summer, carryover or go for the new m coming out.
Snow check is a good option on either the pro or new sno pro...
I think for now best to sit tight and wait for the good deals to be had as well as maybe snatching an '11 xp 154.
But for now I need to ride 10 more days before the season ends