I'm with you Mike...trying to decide myself.
I'm looking at RKE, Aquatronica, and Profilux.
I eliminated ACIII because it does not have the multi-dependent programming flexibility of the other three...so before everyone starts jumping on me about ACIII it won't do what I want it to do as well as the other three.
My take so far is that the Profilux appears to have the fewest problems...virtually none. It has a programming feature called "programmable logic" that appears to be very nice and flexible. Also it has DALI programming for the new LED lighting system by Aqua Illumination that I really like. It is the most expensive of the ones I'm considering once you add in all the power bars, expansion cards, modules, etc. And support is mostly through the dealers, which worries me a bit.
The Aquatronica is very modular and they have added XY Programming which allows for to input states to affect up to three outputs...it makes the programming quite flexible and powerful. I like that they can control Korallia controllable pumps (a lot cheaper than Tunze). Again though, it's a foreign company so you've got to rely on dealers for support, although it seems to be good it again makes me nervous. Also the powerbars do not have manual controls and indicators on them like the RKE and Profilux have...that's a mark against in my mind.
RKE is the most affordable. They release a new firmware patch yesterday that seems to have solved many of their initial problems from launch (expected when any new product is released) They are an American-based company and their support seems to be excellent. Combining their "Alarms", "Multi-timers", and control functions creates a flexible and powerful programming environment. The unit is very modular in design allowing for a high degree of expansion. They are very reasonably priced for what you get and they are releasing several new modules soon including an Advanced Lighting Control module for Aqua Illumination LEDs and moonlighting
That all being said I can't quite decide...
I like Profilux because of the apparent "problem free" product and the Progammable Logic
I like Reefkeeper's modular design, the greater expandibility (max # of modules, etc.) the way the powerbars work, and the price
I like Aquatronica because it seems to fall somewhere between them...more reliable than the RKE...so far anyway....and cheaper than the profilux.