IME, going back quite some time, Leupold CS has always been top notch. It's the fact that I've experienced it first hand over a lot of occasions that I find concerning.
That's my experience with Ruger. Although I think customer service starts with building a product that works as designed, which Ruger struggles with.
I haven't had great experiences with Ruger CS. At one time I had a Red Label, Mini 30, Red Hawk, GP100, multiple #1's, 77's, 10-22's and various small pistols. They're almost all gone now. Some served me well, but I always felt like you could do better in fit, finish, and function for the same or not a lot more cash.
The Red Label I own cracked a couple stocks just back of the tang. Was a common problem with them and #1's, from what I hear and read. Ruger CS did not stand behind the Red Label stock at all. Said it was due to normal use and possibly use of heavy loads. Gun was rated for 3", but I never shot any out of it. 3 3/4 dram, 2 3/4" field loads were heaviest I ever used in it. Was able to find a replacement on GB; that one cracked as well after a few years' use. I epoxied it, and it it's been holding for a lot of years. Kept it as a rainy day upland gun because it isn't worth much with the stock being cracked.
I had a 77 II with a 3 way safety that didn't hold the bolt down when all the way back like it was supposed to. Sent it in. Came back the same way. Had another 77 that had feeding troubles. Sent it in 2 times before they replaced the bolt. Feeding was better, but was still suspect. Instead of being a CRF, it was just a CF.
Through the years I sold most of them off. I should add that these experiences occured 15+ years ago, so perhaps they've righted the ship. Put a couple of RAR's together for guys, and they seem to function and group well.