I'm in my second month of doing P90X (for the first time), and I'm also getting good results from it -- more muscle and more definition.
That being said, I'm still
really looking forward to getting STS, and would stop P90X in a second if STS showed up on my doorstep tomorrow. While I like Tony's silly sense of humor, doing the same few workouts over and over again has gotten old really quickly. One of the great things about STS is the
variety of weight workouts you'll get from it, not to mention Cathe's sweet, fun, and professional personality. STS is not too much more than P90X, and I think that it'll be an amazing product.
Camellia1900, can you maybe ask for some Cathe gift cards or money for the holidays so you can get STS? If you're good at sticking to a long rotation and don't already have some good weight workouts at home, then it sounds like it will help you with those areas you want to work on!

Also, ChaLean Extreme is going to be coming out soon (you can do a search for it on these forums to get more info), and it sounds like it'll be cheaper than STS.