There are so many around! It is not only Quantum and Naiad. There is Wesmar, ABT with their TRAC stabilizers, Rodriguez, Roll Royce, Voith, CMC marine (electric stabilizers) and probably others.
For smaller yacht with no hydraulic equipment the new electrically driven stabilizers seem a good alternative. I think the most important part of the stabilizer is the control system. Quantum seems to be the best choice in bigger yachts so my guess would be that their control system is the most sophisticated around.