I don't think P90X is scary at all. I think the commercials make it look that way because it CAN be scary if you want to make it scary. But it is also a very easy program to tailor to your fitness needs/goals/abilities. Insanity, on the other hand, IS scary (and I love it).
I did a P90X rotation last summer shortly after finishing a 6 1/2 month STS rotation. I was actually convinced I would hate P90X by the end of the rotation because I get bored with workouts very easily, but that didn't happen for me. I think that is because I made sure I tracked all of my weights/reps and kept challenging myself throughout the entire program. I especially did this with pushups, and the results were amazing for me.
But there are things I don't like about P90X. There isn't anything close to enough cardio in the program for me, and I substituted my own cardio in place. There also isn't enough leg work, so I had to supplement with additional leg work. I also found that more form pointers could have been used in some areas (Cathe is really good with form pointers, and I missed that).
I also felt that the program was geared more towards 'show off' muscles, which made it feel somewhat out-of-balance for me. For instance, I felt there was way more emphasis on the quad section of the legs than on the hamstring portion of the legs. I was left with the sense that Tony Horton developed the program by looking in a mirror and going 'This is what I want to look good on me'. And there isn't anything horribly wrong with that because he DID hit all muscle groups, but it just didn't feel as complete for me as STS (as an example).
I have a love/hate relationship with Tony Horton. I find him equally amusing and annoying. But I just kind of learned how to ignore him in some of the workouts and instead focused on getting the best workout I could.
I had great results from P90X. Probably ended that program looking the most 'cut' I've ever looked and THAT is what will convince me to do another rotation (with my modifications as listed above) again. That being said, I'm back to doing another STS rotation, and if you want my opinion on the best strength training system on the market, it would be STS.