I will be going to Beaver County starting this summer. I have heard from a number of different sources (current and former students from there, and current controllers) that Beaver County has the best program of any of the CTI schools (and it's also the cheapest). As ATLTRACON said, you do get "on-the-job" training there in the control tower, so therefore, with their graduates, most of the washout occurs during school, instead of after school. Also, it is an associates degree there. I will be working on a second career already at 25 years old, so I already have a bachelor's degree in education. Because of that I save quite a bit of money not having to take all the math and english crap (especially since I am qualified to teach any of the math classes they offer). You have to go either 3 or 4 straight semesters depending on whether you already have a private pilots license or not. The first semester is just getting the PPL. The second semester is stuff with aviation weather and the 7110. The third and fourth semesters are different depending on whether you're terminal or enroute. For enroute you spend a lot of time in the simulators, and for terminal you spend a lot of time in the control tower.
This is just what I've heard from other controllers, so any controllers can pipe in with what you've seen, but I've heard if you go to Beaver County, it is worth it, if not, just go off the street.