Certainly not the most inclusive environment, nor the cheapest.
I visited Flirty twice as a guest, once for Zumba and once for Cardio HipHop. I found that both times the instructors assumed we all were familiar with the dance moves, and didn't explain much. For all my tripping over my feet, I broke a great sweat both times.
Inside, it's EXACTLY what you would expect from a place called Flirty Girl - pink, sparkly, adorned with butterfly decals and staffed with blondes with skintight workout pants on. Not my thing (I like to look a sloppy, sweaty mess at the gym and not worry), but if you're a big Sex and the City fan, you might like a place like Flirty Girl.