Well, you have to look at the routines. Yes, they are effective. However, so are many other programs. Keep in mind programs like Insanity are not made for out of shape people. They may promise things to people out of shape, but Insanity and other HIIT programs like it are a disaster waiting to happen for out of shape people or overweight people(LOTS of impact in the exercises); That being said, Insanity will improve your endurance and get you in good shape IF you stick to the program and nutritional guidelines. P90X will help you get into shape, lose weight and gain some muscle - If you do the program as intended and don't lazy your way through it. Its just like boot camp, designed to train soldiers and get them in peak physical fitness in a shorter amount of time - except boot camp is more effective because of the time spent with soldiers ensuring they do what they are suppose to. These programs will help you, but so will Scooby. People for some ungodly reason think that they must pay to be in good shape. All these programs do is take fitness knowledge and package into one rather than you having to learn the material from different sources. About a year ago I did Insanity, though I have not done P90X. You know what Insanity was? Almost all the fitness routines were based off of workouts taken from sports training from various sports (Burpees, football stance sprints, mountain climbers, ect). Thankfully I got it for free from a friend who couldn't do it so he gave his DVD's away, but I urge people not to spend their money on these. Scooby will help you just as much, if not more. And for free. Sixpackshortcuts is a total waste of money. Don't get me wrong, their youtube channel has some nice workouts on it - but that is about all you will, the same information they have on youtube for free. Or so I would imagine.
I disagree, I think P90 is a GREAT idea!. Most people NEED someone to help them keep tempo and motivate them while working out. Scoobys info along with countless other sites are great!, but for some they need the extra "push" from someone there doing the exercises with them. Also diet advice and PROPER nutritional information as well as instructions on HOW to make the meals is great and all this is offered in P90.
For me I dont see a need for P90 I have other means of motivation and as many others I take full advantage of the information plastered all over the internet.
This, I think the biggest barrier in working out is motivation, P90x provides a balanced plan, and motivation, like goose I have my preference and motivation, but for those who do curls in the gym once a month.... That being said, P90x doesn't seem like a very good bulking program.