I went with the 13 Assault. Reasons I did is...
-Shocks. Friends I've talked to said that's what they've decided to change out on their rides first, or liked better about others sleds they've tried. Many places we ride, we have to cover some trail, many times not groomed well or post days traffic. Also when have you been the first person up Blue Creek on way to Jefferson? or(Insert your spot here?) Sometimes, but not usual, and when your not the first, what size are the moguls with a 3,4,5+ ft base after a group folks busted it ahead of you an hour/day/s ago?
I also didn't want to have to try sell leftover shocks next time I buy, and you don't get anything for them on trade-in/resale, that's just me.
-Durability of chain case. I like the idea of the quick drive, and think it is or will be reliable, I just suck at jacking the throttle on landings every now and then in said moguls above, or what drops or jumps I may attempt. I need the added durability there to make up for my lack of performance. I don't live in the mountains, so down time for broken stuff sucks and burns up vacation time.Trying to minimize those possibilities as best I can in my mind. If I lived out west, I would reconsider this more seriously, or will with future purchases maybe.
-Welded A-arms for durability, see two comments above.
-Ski width I've left in the narrowest position, and haven't had it in more than 1 ft powder on top of good base. At 6'3" 210# no problem rolling it over. Never ridden a Pro, probably would be easier when compared, but this still seems easy and fun. Looking forward to next year to put it through it's paces and see. I'm coming from a Edge chassis also fwiw.
-Got the Comp track on it as I didn't have a choice, has been a blast here this late season snow and on trail. I'm looking to get a 5.1 to put on it for next years mid season powder.
-Like the option of suspension mounting positions, options are good.
-Mine came with 4 extra bogies, considered putting them on for break in here in MN, not any more after riding some. Need scratchers like was said previously to keep eng temps down on any groomed/hardpack trails, they work great. Even with extra bogies, you'd still need scratchers to keep engine cool, and since you have to use scratchers in those cases anyway, that negates the need for the front cooler, except for maybe ice build up like MH said, but I'm not as concerned about that as others may be. I can't tell a 5-10 lb weight difference personally. Maybe I'll feel different after getting out in the deep someday?
-I do miss the sway bar on the trail, don't in the powder, your preference there.
I do like the argument of going with a standard RMK, and upgrading shocks. I like Pro-Tapers for my body type so I would miss or change to those maybe, but other than that the Standard RMK add premium shocks covers most of my amature concerns. If I were snow checking, I would seriously be looking into that myself.