Very pleased with them. The instructions could be better (such as telling you clearly that OGC requires rotors to be changed). Currently using LTC up to 50%, which it rarely seems to hit, but water movement seems good and they are quiet. Sand is gradually moving away from the edges where it was piling up with the Vortechs and steadily making it's way back to the middle, which was down to the glass with the Vortechs. Hopefully it will even out nicely... or I'll end up with the opposite issue.
I've got them no more than two inches below the water at each end of the Reefer 350.
As I have taken the backing off the tank I was considering mounting them vertically up against each side of the weir so they would barely show in the tank, purely for aesthetics. Is anyone running a pair like this? How is the flow and surface movement and what mode are you running?