If you are looking at the Maxspect, go with the G2....easy to upgrade/swap LED's, near silent fan and 30 watt Cree's on several of the units. I have the G2 160w on a 24x24x18 and the unit is comparable to a 250w HQI with T5 actinic. You could do two of the 160w G2's on a 90 gal......
I just ordered 48 blue cree leds and two 48" heatsinks with the meanwell dimmable balast to compliment the new dimmable powermodule coming in next week.