I have Intense Moves and really enjoy it, but I don't have a lot to compare it to... the only other interval workout I own is IMAX 2. Cathe is definitely harder and more creative, but sometimes I don't feel up to IMAX 2 or the choreography... and Intense Moves fits the bill perfectly. It will definitely push your heartrate past its anaerobic threshold, leaving you huffing and puffing and sweating like crazy... but the blasts feel more manageable to me when they are each timed for exactly one minute, and there is a countdown clock on the screen. Also, Gin shows variations of each power move, so you can make your blast "hard", "harder", or "hardest". For this reason, it could be good for someone trying to build up to Cathe's intensity. It's also a little shorter, a good option to have on hand for those time-crunches we all face.
But when you have lots of time, loads of energy, and want to have a ton of fun, IMAX 2 is your better bet.