True Tabata (i.e., the program Dr. Tabata developed and researched) is 4 minutes long -- 20 seconds max intensity, 10 seconds recovery -- for four minutes. THEN STOP. If you're doing "Tabata" for 30 minutes, you're not working out at the maximum intensity. It may be interval training, but it's not the Tabata method.

Have you done any googling of tabata? It's not a class, it's a method of performing high intensity interval training. Alot of gyms now offer classes that use the tabata method but it's not crossfit or aerobics. Google it and you'll find lots of stuff written about it. You can do it right in your house or at the gym using any piece of equipment.

Has anyone done it? Is this like Crossfit without weights or is it more like glorified aerobics class?

I'm looking to shake up my workout routine but things like step aerobics don't really interest me.