I only have CLX and I love it. I love the results (lifting heavier, more definition) and I also love that most workouts are about half an hour. The program comes with a great cookbook, a Kitchen makeover and a motivational CD (nothing particularly new, but it is always good to hear and a great motivation!!! You can leave it in your car!). I also like that Chalene goes around and talks about proper form. Others find this distracting. I love Chalene's energy...some don't. You get the idea.
I love Cathe and put her at the top of my list, but have lots of good things to say about CLX.
You will find lots of people here who love STS and also love ChaLean (one or the other AND both). You probably need to define your goals specifically and then we can help you decide which is for you.
You might want to do a search, too about CLX vs STS. There have been lots of discussions about both. Both are good for different reasons and appeal to many for different reasons, as welll!
Let us know what your specific questions/goals are and we can help from there!
Good luck!
Jenn