I don't doubt the good intentions of the folks at CCS, but I don't agree with what they're doing, either. The thing about voluntourism like this is that it gets you into the country and out so fast, that I don't think it's possible to really have an accurate picture of what (if anything) you accomplished. The phrase volunteering abroad has such a positive ring to it, that I think a lot of people sort of take it for granted that they'll be making a positive difference-- so they don't put much real thought into it themselves.
I was a teacher at a couple of local schools. Like all of the other volunteers, I had no teaching experience or knowledge, so I don't think that I accomplished much. A lot of people volunteered at orphanages, which was fun for them-- after all, everybody loves to play with cute kids, and when you see all those smiling faces, it's hard to think that you're NOT making a difference (if nothing else, you'll get a saint like facebook profile picture out of it). But little kids form bonds extremely quickly. So when they go through their early development constantly forming bonds with people who show up for a couple of weeks and then leave forever, severing those bonds, that actually seems kind of . . . bad for them.
But doesn't CCS advertise on their site that they consult local organizations to find out where volunteers are needed? Yes, but . . . here's the thing: I spent two years in the Peace Corps, and what I found is that for a lot of organizations in developing countries, white people are--sadly-- a symbol of prestige. There aren't many organizations that are going to say no to white people being associated with them. A friend of mine who taught some English in South Korea put it this way: "Most places just want a white face in front of the room." The big difference between the Peace Corps and CCS, is that in the Peace Corps you learn some of the language (the idea of meaningful language learning in a few weeks-- like CCS advertises-- is a joke), and you have two years to figure out which of your assumptions are true and false, and gravitate toward the more meaningful work. CCS is limited to only organizations in which they can plug in many volunteers who don't speak the language, don't have any training, and will be there for twelve weeks at the most, and in most cases much fewer.
The fact is that a lot of volunteers are there to party. In my program, volunteers spent most of their evenings watching Sex and the City in the CCS house, and their weekends partying on the beach. In fairness, I was participating in the Trang program in southern Thailand, which seems to have been discontinued. But it's also hard to imagine that the culture in other programs is that much different, when most of them are intentionally near prime tourism spots. There are a few good things about CCS-- the staff are dedicated, and you will enjoy your weekend travels. But I don't know that those things outweigh your dubious non-impact/ possible negative impact. Just think about it. You could do a heck of a lot of responsible tourism for the amount that you'd spend on CCS.