I have taken CSS but not YCRS (yet). I did levels 1 & 2 (not the 2-day school) back to back. I think the drills are good and meant to build upon each other, you will do 5 drills each one building upon each other (throttle control, quick-turn, 2-step, 3-step, etc.) so by the end of the day, you will be using all of them in conjunction. The next level was mainly about vision, so you use 5 previous day 1 drills and build with 5 more vision. Level 3 includes more body position, and you go from there. As with any school, you will learn if you have the right attitude. I felt like I improved, but not as much as I wanted. I kept on using what I learned and after a few more trackdays, it started to click and I was going faster.
What Meat is referring to with CSS' teaching style is that Keith Code wants you to think about your riding, so they will ask you questions and want you to give them answers. I can see how this is frustrating to some riders, as you either don't want to deal with it, or because you know the answer, but want them to give it to you so you can ask a deeper question regarding it, may not work. A friend of mine didn't enjoy CSS much. He said he's been told since the class that he felt he had to undo some of the things he learned, so that he can be smoother. He also wanted more one-on-one time, and a few other things that he didn't really enjoy.
YCRS - when they closed down last year, I thought I may have missed my opportunity, but they're back, so I'm saving up. $2.5k is a lot of money, I personally wished they have separate classes with more riders and a BYOB option so it's more accessible to all riders. I'm looking forward to this school because they are heavy on braking (trail braking) and since I've started trail braking into my turns, I have felt it's improved my front end feel and understanding. I've also have not heard a bad thing about them either. I've spoken to racers who said riding 2-up with Scott Russell was scary. One guy said the entire first lap he didn't even open his eyes, then got the hang of it, he didn't know you could go so deep on the brakes into turns. The curriculum is excellent and worth the money.
My advice to you:
ATTEND A TRACKDAY(s), especially where you plan to take the school, so you can learn the track. I had to learn the track while learning drills, so you can strictly focus on the lesson without worrying what the next turn coming up is. You can get free training from trackdays as well, so you can be at a higher level of riding before you take the school, and get more out of it. The other side is you can learn proper techniques without having to unlearn bad habits, and probably make more gains by taking schools. Either way you go you're basically looking to achieve one thing, improve your riding, which both schools will do. Good luck!