I used Sylvan for my daughter and would not recommend them or use them again. It wasn't horrible but I spent $5,800 for their reading program for my daughter and it did nothing. She didn't improve the entire time she was on the program and they were "mystified". Their solution at the end was of course to sell me more sessions. I declined. And btw, my daughter did catch up on reading, it just took some time. I think in her case, she was just one of those kids that wasn't ready to read at age 5. I did later on pay for a teacher at her school to work with her a couple of afternoons a week fora bout two months and that helped far more and was less than half the cost per hour of what Sylvan charged. And it didn't involve up front money, contracts or anything else we couldn't stop at the time we felt it was time to.
I think programs like Sylvan might be good for some kids, especially older kids, I know they have SAT prep and programs to help with study habits etc. But the bottom line is that sometimes kids who are behind in school are already stressed to the limits, overworked beyond thier ability and feeling "weird" or "dumb". When you add to the mix intensive sessions that cost an arm and a leg it puts a lot of pressure on everyone.
I recommend to parents they ask the teachers that work with their children what they recommend. Most teachers I have talked to and know don't have a fondness for Sylvan. Even though to be a Sylvan instructor you have to be a teacher (if memory serves). I have had two friends who are teachers who worked at Sylvan while their kids were young and they needed some extra income without full time hours. They both left Sylvan and didn't feel at all good about the program.
I would much more recommend you find a teacher in your school to work with your child. They know hands on the curriculum, they can work with your child's teacher on what exactly needs to be done (your child's own teacher might tutor) and again, if you decide its not working you just stop the sessions without as much financial obligation and hassle.