I've done P90X once seriously and once or more not as serious.
I've attempted Insanity a couple of times and could never get past the first 5 weeks w/o injury or over-training issues. I was trying to play tennis or run at the same time. When I say run, I'm usually training for a 1/2 marathon or at the least keeping my longer runs at 6-7 miles and my shorter runs at 4-5 miles.
I've done Rushfit at least twice.
I've never followed any of the eating/dieting plans.
Here is the way I'd rank them followed by my reasons:
If you do it and give your best, you will be fit, fast, etc. and see benefits in all aspects of your life. The drawback is that each workout will take at the minimum of 75 minutes. You'll also have to push yourself and it requires equipment too. The time and equipment is a drawback. It worked best for me when I was doing it with 2-3 other guys and we were pushing each other to show up, out do the others in reps, etc. I gained 10lbs the first time because I had no upper body muscle because I had become a runner and neglected the upper body. I was lean and mean and could run and jump as well as many athletic 25 year olds when I was 1/2 way through. My issue is that I'm 40 now and I lose it just as quickly as I gain it. I really have to work hard to keep the superior athleticism. As I said, it is difficult to maintain the commitment and motivation w/ a busy lif of playing tennis, basketball, working, and taking my kids to their many activities. P90X is the best if you can commit to the work. Tony is annoying but you learn to love him after awhile and even miss some of the ridiculous things he says.
Rushfit is great for core strength and I don't mean abs. If you do it all the way through, you'll find doing air squats and lunges to be nothing and feel like you could easily do 100s w/o ever getting tired. Good for tennis? I think so. I wish it had different warm-ups exercises depending upon the day. It gets really old to see and hear the same instructions each and every day during the same exact 12 minute warm-up. If you canb fight through that and I recommend you do since it is a good workout in itself, you'll like Rushfit. The average time commitment is probably 50 minutes total. That's better than P90X. However, it is much harder to push yourself in these workouts when you are punching and kicking in air. I wish I had a heavy bag nearby but that would involve equipment and Rushfit requires very little equipment; maybe a couple sets of dumbbells is all that is needed. Unless you really go all out and crazy, it is hard to get explosive fast through Rushfit. Its strengths are definitely in the core area and building strength. I was impressed with what I saw as similarities between Rushfit and the workouts my daughter did when she was rehabbing from ACL reconstruction surgery. Rushfit does many of the same types of exercises to help you strengthen your legs to greatly reduce the risk of injuries and that is also a big, big strength. If Tony is annoying, Erik is ridiculous with his arm/hand waving and over analyzed instructions. It is also a bit much to hear the same instructions every day since the warm-up and cool down are the same with each workout. Honestly, if you can get through it, it is good. The warm-up is a good 12 minute workout all by itself. Rushfit is behind P90X but just barely. If you aren't going to give it all you've got and really commit to P90X and don't have 75-90 minutes, you should really consider Rushfit. I definitely agree w/ Tennis34's ratings of the videos. The 4 and 5 stars that he gave are to the best workouts and if you just did those, you'd have a great workout and lots of fun.
3) Power 90
This is the workout that led to P90X from Tony Horton. It is comprised of 4 workouts; Sweat 1-2, Sculpt 1-2, Sweat 3-4, & Sculpt 3-4. It is simple. Alternate the 1-2 series day-to-day for 45 days and then alternate the 3-4 series for 45. It is sort of an all-star shot of what is done in P90X but the workouts are only 45-55 minutes and does a little of everything each day instead of focusing on a particular section of the body. It is simple and effective. Not as much fun as some of the others but does a little for you and I really couldn't complain about any of it. If time is an issue, this could easily be your and my #1 workout program. It will help you become explosive, etc.
My 40 year old body can't take the pounding. Enough said. If I were young and in good shape, I'm sure it would be better. As it is, you can get all of these moves and strength improvement from any of the above mentioned programs. Not worth the injuries for me.
Nike Trainer for the Xbox 360 w/ Kinect
I just started this 4 weeks ago. I love it so far and am still learning it. It is fun and really counts and calculates a score based on how you do the moves. As I've said earlier, I need explosive speed. I especially need it when I play basketball against 25 year olds and doing these workouts have helped me keep up. I've gotten the explosiveness back a little but it will always be a work in progress as I'm 40 and lose it quickly. The workouts are between 35 minutes and 1 hour. It depends upon the number of rounds you want to complete. I usually do at least 2 rounds. You do many of the same exercises from Rushfit, Power 90, and Insanity along with new ones that are fun such as simulated dodgeball and another called split decision where you have to jump, duck, or move into openings of a moving glass wall. It requires very little equipment aside from the Xbox w/ Kinect. It is my #1 favorite so far and I doubt it will change. It really does adjust to your needs and tracks your reps and progress. If it could be made so more than 1 person could workout together at the same time it would be amazing but it is really cool as is.
I recommend Rushfit to anyone who has minimal time to just do the warm-up each day as it really is a good workout in itself at only 12 minutes. When I was cleared to start working out after breaking my foot this summer, I spent the first 4-6 weeks just doing the Rushfit workout each day. It helped my strength getting back since it is non-impact and it also made me numb to Erik and his repetitiveness.
Back to using POGs. Why did I ever leave you dear friend?