My experience is on a 6x54 stealth. Low PAR (less than a Tek), the fact they spaced the reflectors up to clear the ballasts so they were too close to the lamps (Some even rub) is part of it, lack of cooling and no vents in the top so the ballasts get cooked probably doesn't help either. It looked to me like the designed this nice case then figured out a way to fit all the guts inside.
There was a very long thread where a guy with a T5/halide fixture of theirs had issues and it took them forever to resolve it. For what they charge there is no way in hell the guy should have had to open the fixture up and do his own electrical trouble shooting. It was a cooling fan issue in the remote ballast box. You would think they would have just sent him a new box rather than jacking him around for months.
On the positive side the finish was very nice but for the money they are asking I would want to see performance figures first.