I have completed 8 weeks of Focus T25, I have gotten in all my workouts although I have had to double up workouts a few times. The standard T25 program is ten weeks long, five weeks each of Alpha cycle and Beta cycle. There is an optional Gamma cycle which I also purchased when I bought the program. Alpha focuses on cardio, Beta focuses on the core, and Gamma focuses on strength. Due to a hip and knee injury, I have being doing the modified workouts.
Only 25 minutes a day. The workouts are easy to fit into a busy schedule and most of the workouts are pretty enjoyable.
Almost anyone can do T25. The workouts are not catered for those in shape already and there is not insane plyometrics and crazy moves you will see in Insanity. The modified option makes it possible for those with injuries, deconditioned, or out of shape to to the workouts. Even those in good shape will get a good workout although it is not incredibly challenging.
Those who want decent resistant training will not find it here. I actually wish I would have skipped Alpha cycle and started with Beta because I did not need six extra cardio workouts/week. I would recommend that to others who are in good shape and need a more well rounded program. Of course, you would be wasting half the program.
All in all, I think T25 is a good program. I would recommend it for intermediate level exercisers or those who just do not have time to commit to a more comprehensive program.