I just finished Week One of T25 and just wanted to pass along my thoughts. By way of background, I have been doing Cathe for about 15 years now. I should also say that just prior to doing T25 I had been on a 6 week hard rotation of Cathe workouts but had just had a week of vacation and had not worked out in a week when I started T25.
Overall, this program is much less intense than Insanity.
T25 Cardio- This one is hard and he is not kidding, there is not one second of rest in the 25 minutes. I thought this was very challenging but while there were one or two points during the 25 minutes when I had to pause for a second or two (or 3) at the end of the workout, I felt like I could have kept going. Also, and this is true for all the workouts, the modifications are SOOOOO modified that I don't think anyone would get a true workout if they did all the modifications.
T25 Speed 1.0- This one is not as hard as Cardio 1.0 because you do get breaks for stretches and balance challenges. Didn't feel at any point like I needed to stop or take a break. Good workout but again, I wasn't wiped out at the end.
T25- Total Body Circuit- I would rate the difficulty of this one in between Cardio and SPeed. It was challenging and I think I took a break for a few seconds once during the workout.
T25 Ab Circuit Intervals- When I was doing this one, I thought it was fairly challenging but the next day my abs were not sore at all. Again, this is after being off workouts for a week. I don't think it is as hard as the abs in Insanity.
T25 Lower Body Focus- Good lower body work for glutes/hamstrings/calves. But compared to Cathe's leg workouts (with weights) I would rather do Cathe's weight loaded workouts.
As a side note, the program says 25 minutes a day for 5 days a week. However, on day 5 they actually show 2 workouts on the calendar but then say if you can't do 2 workouts on one day, just workout 6 days instead of 5. So it's really 25 minutes 4 days a week and 50 minutes 1 day a week or 25 minutes 6 days a week.
Overall - not as hard as Insanity. I like Shaun T as an instructor most of the time. And as a final thought, these may be good to supplement weight workouts but I can't see getting major results from these alone. Again, the modifications are so low impact, not sure they do much.
Just my thoughts for what they are worth.