Few things...
Norona means well and is a good dude, but he's also paid by BRP. Take his input for what it is.
I've ridden all 3 sleds. I like them all for different reasons. I'm not here to say one brand is better than the other. I think its important for me to note this just because some people exude cognitive bias around this alone.
There is no question Ski-Doo's skid design is dated. A torsion bar is not as effective of a spring for a number of reasons. Proof is in the pudding, as they say, with all of Ski-Doo's athletes moving away from the setup (if they are allowed per the rider contract). The fact that no other manufacturer uses it in a mountain application (or snowcross applicatino) further showcases this. Anyone suggesting Doos work better in the bumps really ought to try bringing their speed up. At higher speed the doo is terrifying in stock configuration.
Considering Ski-Doo already has a relationship with Fox, I too am surprised they don't offer this as a snowcheck option. I'm also surprised they can't seem to get the valving right (fox) in out of the box configuration.
This is where guys like Tom comes in. Anyone who has ridden a setup from a guy like Tom and compared it to stock will attest it feels like an entirely different sled. Plus, its lighter, more durable and easy to configure to each riders desire. Getting rid of the torsion bars is a huge improvement.
The other OEMs offer better shocks out of the box than Ski-Doo - no question. Yes, the Walker Evans need a revalve (something you can't even do on the SP), and the Cat is a bit fiddly, but both those packages are far better than the stock Doo package. With a revalve, I'd say both are better than the KYB!
I almost wish you could get the sled without shocks, though I'm guessing that'd only save you $200. Maybe less.
Anyway. Just my musings.