Imax 3 was alway my "hate it, but want to work hard" workout of Cathe's. I've done Insanity but Imax 3 was a dread factor for me, thinking I couldn't get through it. I've been on a XT rotation (BTW, love the burn sets and 100 reps challlenges, seeing definition I haven't seen in years) and Tabaticise scared me. I have made it through all five Tabatacise chapters a few times...of course with a little extra pause from DVD player between some of them....and love that workout. Works like no other, feel incredibly accomplished completing all 5. So, last night I decided, due to music in Imax 3, to put it in and see how i did --- I did well, but I have to say my lower back and knees really felt Imax 3 vs. Tabatacise, even though both are high impact.... With all Cathe's new offerings not sure I'll ever do Imax 3 again... anyone else feel the same between Imax 3 vs. Tabatacise?