Zumba has recently replaced Jam at my club. I really love Jam, but unfortunately the students feel more successful with Zumba and the numbers speak for themselves.
At first, the music horrified me, but you can mix in your own songs, and just like any class, depending upon the instructor, Zumba can be a great cardio workout. Although it can be repetitive for me as an instructor, the success rate is higher for the participants and they keep coming back for more, WITH THEIR FRIENDS!
I have to admit, I don't miss the stress of learning new dance moves every few months! It takes me much less time for me to learn Zumba routines. 
Even though my Jammers miss it, they're still gettin' their groove on in Zumba!
So keep on Jammin' for me!
Good luck with all of your programs.
Bottom line...get more people movin'!