I've gone to maybe 12 classes since mid February, life got in the way a lot in April & May (vacation, totaled car, laid off, etc, etc). Not nearly enough to see a whole lot of results on the scale, but I have noticed some other non scale changes.
I am physically stronger and I have better endurance now on my 12th class than I did on my first class. I used to do only the low impact moves, and I was sore for days later, but now I do a blend of low impact and high impact moves, and am not sore for days.
I have definitely gotten value out of my classes.