Sara,
The only equipment you really need are a set of dumbbells and a cushy surface (maybe some puzzle mats) to do plyo on. I started P90X by doing heavy 1-arm rows and pullovers instead of the pullups and it worked fine. Then I moved on to the door bands, which have a different feel to them, but are not really necessary.
P90X can definitely be more intense strength-wise than CTX. Its not a cardio-focused workout rotation, so that aspect is not as intense (but everything in the rotation fits together nicely, even though a workout like Kenpo X--kickboxing--may not be intense on its own).
$150 is a lot of money, but it's one of the best investments I've ever made (man, I sound like a broken record, don't I ....just part of my P90X love affair!). For that, you get 12 different workouts (5 strength workouts, a plyo workout, a yoga workout, a core synergistics (functional strength) workout, a cardio workout, a plyometrics workout, a kickboxing workout, a stretch workout, a tough core/ab workout) a detailed manual showing exercises and detailing rotations, and a detailed nutrition manual ( more like a big spiral-bound notebook) with recipes. If you don't count Ab Ripper (which is a 15-minute add-on that is also included on all the weight workouts), each workout is a little over $12 (and they are hour-long workouts, with Yoga X being 90 minutes), plus the manuals are free!
Jeesh...wish I got a commission from Beach BodY!