Have both. The SP rides pretty much the same as the XC. The difference I think would be under hard use on rough trails. The SP is a switchback and the XC a 137. Not much difference in push on either as the sb has tipped rails. If I were buying today I would consider the 650 sp due to price. As it was we paid only 500 more for the xc 850. Prices were awesome in 25 12499 plus tax for the xc, then in 26 11999 for the sp, both were leftover 24s. Unless we have some real crappy winters we will not see discounts like that again. The leftover cat 600s at 14500 are a real solid deal and most likely the best deal out there unless you want a used unit. I know ot is hard to part with that kind of money for something you barely use, but I say do it. Time flies and as we age there is no guarantee you will be physically able to ride in the future. Right now I need surgery on both wrists, hoping I can get through this season before I do it. But I know 400 to 500 km days are a thing of the past. Just pull the rrigger and get what you want, in a few gears the 5k more you spend today will not matter much.
Well I bought a Garmin watch. I wanted a Smart watch anyhow and Basspro had a great price. Way too many features but it will give me hours of entertainment trying to figure out how to get it to work!
And I know what wife is getting me for birthday!