I LOVE Zumba!!! You really need to search out a good instructor though or at least one that suits your style. My instructor has a background in hip-hop and belly dance so that really comes through in her style.
I went to a Zumbathon Friday night and there were at least 6 different instructors. There were only 2 out of the bunch that I liked. One had routines that were straight out of TurboJam and one was just ridiculous with her choreography. There was one guy that had a disco themed routine which was fun and he also had a capoeira/african themed routine.
Usually you can get drop in classes for under $10. If you go to Zumba.com you can find classes in your area.