To throw my experience out there; I've been using Apex for 5 years now and absolutely love the system, and its ease-of-use. I, however, am an equipment junkie, so I also invested in a full Profilux 4 system along with the new KH Director..to justify the purchase I said I'd run the Profilux as a backup redundant system, as I've got a 500g reef and a separate fish room with a total 900g of water volume in the system. I've had the Profilux system sitting on a shelf plugged in but doing nothing, because so far I've gotten frustrated within minutes of logging into it and find it very, very difficult to get simple programming accomplished.
However, I will mirror someone's earlier sentiment; Marco with GHL customer support has provided, by far, the greatest customer support experience I've ever encountered with any company. He's gone above and beyond trying to help me get up and running..I've never had anywhere close to that service with Neptune. But on the other hand, I've never really needed that much support with the apex
My last caveat: I'm definitely not sufficiently motived to learn the profilux language since it's just a side project and the Apex is running the system..so if I was depending on the profilux to support the system, I'm sure I would have tried much harder to learn its very complicated and non-user friendly interface