Hi! I coach the Xcel program up to platinum, and I'll make this answer as simple as possible. If you want to 100% commit yourself to the sport, then you should join JO. Xcel is made for gymnasts that enjoy the sport, but also want to play other sports or have a life outside of gymnastics. Doing JO is like having a job. It's very hard work with long hours. If you want gymnastics to be your life, then JO might be an option for you. If you want some outside time to yourself, stick with Xcel and just have fun with it
I know this response doesn't consider your skill level or requirements to get into JO, thats a whole other topic that some people have already covered in this thread. Good luck!