So many variables on suspension geometry and so many different personal preferences as to the performance expected. It's hard to say what is the best for any particular person. It's also why you read so many different opinions on what kind or brand of shock to use.
Different positions on the sled have different ratios for shock travel to suspension travel. Using all the travel (as compared to using only 75% for example) at all speeds would be ideal and the most comfortable, as long as it never bottomed harshly. A good valve stack will let this happen with the proper spring for your weight. A good valve stack will make spring selection for what you want out of your ride easier too.
Triple rate springs with cross over tuning allows a more generic valve stack to be used (one size for all?) but now you have three springs to select and the cross over points (where the total spring force starts to ramp up as one tender spring is taken out of the equation by the spacers bottoming out) to play with.
100 thou difference in a tender spring travel can be quite noticeable once you select the proper springs (sometimes there is only 4" of shock travel for 13" of suspension travel). Depending on the shock position, this will effect things like transfer, or body roll, or how fast your sled gets up on the snow.
Saving grace of triple rates is you don't have to take the shocks apart (internally) to fine tune. You just need to remove the springs and change the cross over points with spacers (after you get the right combination of springs).
A single air volume shock like the Float 2 will always be a compromise between ride height, total travel used and bottoming resistance. It is best used where shock travel is close to the total travel (Baja buggys?). That's because the finite air space creates an exponential spring. Most sleds (and their shock travel to total travel ratio) are designed with straight rate spring in mind.
Simple example; 100lb per inch spring. 3" of shock travel (maybe 6" of suspension travel) equals 3x100 or 300lbs of spring force plus your preload. One more inch of travel and you increase that number by 100 more lbs. On a single chamber air chamber shock, if you need 100psi to hold you and you sled up you may have 500lbs of spring force after 3" and the next inch adds much more because the volume dictates the spring pressure not the travel.
In the rear sissor position this could severly limit your transfer, in the middle position this could stop the suspension from compressing more to climb on the snow instead of trench, in the front position it can cause a ski to dig in instead of allowing it to climb on the snow.
IMO the only position on a sled they may be acceptable is front suspension (but still a compromise)
The Evo chamber models (not the added air canisters you saw a few years ago) is more like a dual spring set up with a tunable cross over point (to a point) with different pressure chambers. But you still end up with and exponential spring towards the end so you limit travel.
10" of travel "feels" way better than 7" of travel even if the valving is out. But, 7" of properly controlled travel can keep you sitting more than 10" of poorly controlled travel on an ungroomed trail.
I'm a spring guy lol. I can tune my sled (any shock) to be pretty good with triple rates (big selection of springs over the years lol) but the weight penalty is big (be honest and put the triple rate shocks on the scale). It's 100 bucks a pound for the cheap weight savings so why add to the cost of your sled lol.
Valving is the way to go, with straight rate springs (for the your weight).
IMO for a mountain sled, if you have a keeper, if you are within the average rider weight the manufacturers use, stick with the stock springs, buy a good quality (high flow internals, good shaft and good body,,, stock WE's ain't that, but they are light lol) from a reputable shock rebuilder. Forget about all the clickers and chambers (because once it's set it's set and could just tape them up lol). Be honest to yourself and the builder and let them give you their best first shot.
You may hit it on the first try (especially if you have the normal one or two shocks are shot already). If not, an honest conversation with the builder will dial the valving in no more than two trys (usually one).
Bling is nice but it is not necessarily performance.