I came off a 2018 6000RXC which I put 7000 miles on.
I went to a 2021 650 VR1 which I have 4400 miles on.
The Cat was superior in the tight woods. Nothing handles like a 6000RXC. Nothing. Stay planted and is HIGHLY predictable. It takes a little more effort in the shoulders to hold your line in choppy conditions, but the front end of that sled is amazing. You are sitting really low to the ground though, which has a lot to do with it. Nothing or nobody can keep up with me on a 6000RXC on most trails - except maybe a better rider on another 6000RXC. BUT - there's a price you pay for that awesome handling, and its in Cat's poor rear suspension. I think that slide action rear skid came out during the Clinton administration!!!
As mentioned by others, the Cat has a better headlight. I'd also like to add the Cat has a better raspy sound to it - but the 6000RXC also has a lightweight "race" exhaust on it from the factory which makes it one of the best sounding factory sleds ever sold.
Other than that, every single thing about the Matryx - and the VR1 - is far superior. Refinement, NVH or lack of, electronics, rider ergo, fuel economy, power, storage and accessories, and so on. It all goes to Polaris and by a wide margin.
After 300+ mile days, I feel way less fatigue on my VR1 and at the same time I'm not getting any younger either. That's probably the biggest compliment you can give to the Matryx. I ride big mileage days all the time throughout the winter and the Polaris just does it so effortlessly with its ideal weight, balance, linear powerband and good suspension.
Both sleds have been bulletproof reliable for me.