I like the Aquatronica, I currently use one and it is a perfect fit for my needs. The drawback is that it is on the expensive side & very intricate to program, on the other hand it is very customizable and expandable, the display is very user friendly.
I have also owned & used the Reefkeeper, it is also a very nice unit specially if you have a budget, the drawback is that it is not as versatile and expandable as the other controllers in the market.