I think there are many different reasons that dancers dance and teachers teach to recorded music. One is to give the students a feeling of accomplishment. Many students go to bellydance classes just to learn a few steps and never take it beyond that.

Dancing a taqsim to live music requires a vocabulary of steps large enough that the three minutes or so that the dancer is out there isn't just a series of shimmies and drops. Kathi Richards mentioned a workshop called "Beyond the Hip", where a teacher (I don't remember who) teaches how do incorporate various moves such as hand gestures and head slides into a taqsim routine.

The other is confidence. Many dancers I have encountered don't want to solo, ever. That is why they dance tribal-style, they are more comfortable in a group. Many tribal-style groups dance to live music, most notably Gypsy Caravan and FCBD (Helm), but again, they have a vocabulary of steps that they can draw from to match the music.

I have had the privilege of dancing the taqsim to some of the best drumming I have ever heard. Having enough confidence in your drummer to play something that you can dance to is another challenge in dancing to live music. Communication between dancer and drummer is key. Many dancers don't have the privilege of dancing to the same drummer over and over enough to develop that kind of communication.

I agree, now that I have done it, live music is definitely best. I am hooked! I am looking forward to at least two workshops this year to improve my taqsim-February is Princess Farhana's Extreme Taqsim at Dances in the Desert, the other is Angelika in Baja in October.

And I believe the term is no longer Robo-Dancer but Zombie-Dancer (new year, new word!)
Just my 2 euros......