I currently ride a 2020 850 Backcountry XRS. Its slowly becoming a summit with a solid rear arm (no t-motion)
Ive had a few Polaris sleds in the past, and a few Ski-doos. I would say I'm a little Polaris bias to be honest, but buying a Polaris worries me a little.
I love my doo for a few reasons, the main one being the motor. Its damn near perfect. It starts first pull every time, even in -30C. Then the shot start takes over for the rest of the day. I'm not entirely sure I can ride without shot start anymore.. I could go with the ancient electric start set up Polaris has, but then there goes the weight savings!
The etec doesn't foul plugs (EVER) I have never heard of electrical issues with it, and it idles and runs so clean. It really is the best engine in the snowmobile business in my opinion.
A lot of guys dislike the rear suspension because of the torsion springs. Personally, I don't really mind it. It would be fine by me if they put a new suspension in it, but right now.. Its ok for me. I have to ride trail to get where I'm going. So the cushy feel on the trail is an added bonus to me. I also like to carry a fair bit of weight on my sled, so the ease of clicking up the spring compared to adjusting a spring on a rear shock is very important to me. (I also ride two up with my kids, so the torsion springs help there as well) I find the sled loves to be jumped as well, and it does what it needs to do while I'm playing in the trees as well. I wish it wouldn't wheelie so much sometimes... but that can be really fun too.. so its 50/50 there.
I very much like the fit and finish of the doo as well. I feel like its been professionally built, very respectable craftsmanship, and top quality materials used as well... for the most part.
So, that's what I like about the Doo... Now on to the Polaris.
The polaris just handles so well. I know sidehilling is just a piece of the puzzle in the grand scheme of things.. We do so much more than just sidehill when we are riding. But the Polaris gives you so much confidence, I find my self wanting to sidehill and get into tricky areas more often. I can try to get the Doo into these areas, it'll take a little work, or a couple attempts. but it will do it... just not as easy as the Polaris. The balance/feel while in a sidehill is so much better, its like thats what the Polaris was designed to d, more than anything else.
I really like how narrow the Polaris is. The sled is purpose built for technical riding. It is also much easier to work on. Break an a-arm on a doo and its a fairly difficult job to get back on the snow that day. Polaris needs about 30mins at the most to change an a-arm. Same goes for track changes or, rear suspension work.. its just easier.
The Polaris will get on top of the snow much nicer, and in almost any situation you don't have to worry about trenching like the doo will do sometimes. I hardly ever get either one stuck... Its just that I think the Polaris rear suspension works better in that situation.
As for the steering, laydown post vs forward/straight post... I don't really care much for that debate. You will adapt and get used to whatever you use.
In the end, I ride a doo because I don't want little nit picky issues. I do miss the feel, and the handling of the Polaris, but you can make a Doo pretty good if you know what you need.
I strongly considered a Matryx this year, it looks like the sled to have for 2022. But financially it didn't make sense for me, so we will see what 2023 brings us. I could be ordering anything at that point. Sorry for the long winded response.. I have a little bit of time on my hands lol.