There are a lot of threads like this on the bigger sites. Both Reef Central and Reef2Reef have had a lot of discusion on this topic. It really comes down to what do you want it to do, how much do you want to spend, and how much manual coding do you want to do? If price is no object then I believe the Profilux is supposed to be the best money can buy.
I have an RKE and it works pretty well but if I had it to do over I would have gone with Apex. If you want the best controller on the market and have allot of money the GHL profilux 3 wins hands down IMHO.
I just spent the last 3 weeks researching the hell out of these, eliminated RK right away, apex vs reef angel. Went with reef angel. Don't have it hooked up yet. What swung it for me was more customizable and a little cheaper out of the gate plus you get ph. Both are solid units and will cost about the same if you end up adding a few modules. Apex has nicer controller but you don't use it much once you get it all hooked up.
thanks for all the input, just struggling cuss I have 4 diff tanks and don't need all the control some have more concerned about my office tanks and leak control can you hook up leak detectors and have them alert you at home
If you're looking for basic functions, you might be interested in the ApexJr. Don't know the limit on expansion modules though. A RA will do what you need, that's what I went with.