I've not, but I am a long-time practitioner of another art. My suggestion is that you attend a few classes as an observer - pay attention to how the students interact, how the instructor speaks to his students, and what the atmosphere is like.

Most of the best training environments will be serious, quiet, but positive and respectful. Aggression, bravado, condescending tones, or an attitude of hostility towards visitors - or worse, trying to get them to commit to long-term contracts - are major warnings signs.