I had a set of DT Swiss RR21 dicut in the past and found them to be a fantastic set of hoops. They were absolutely bombproof and rolled beautifully. From memory, I think the weight was ~1400g which is not to shabby for an aluminum wheelset. I rode them in all weather conditions, up and down some nasty inclines. In conjunction with Swissstop BXP brake pads, I never had any issues slowing down, even in some horrible scenarios.
I also had a set of Mavic Cosmic Carbon wheels with exalith rims. The stopping power of those exalith rims / pads is quite something.
If I was going to pull the trigger on a new set of rim brake wheels for a lot of climbing, I’d probably go Mavic R-SYS SLR. Sub 1300g and exalith rims.