I can only speak for the Neptune and Reef Angel products as those were the two I looked at before buying the Neptune Apex...
Apex Pros: Web accessible, easy to program, controls anything I need it to control, can handle the LED dimming of my future LED build, great service, mainstream controller talked about on many large and small reef sites and clubs
Apex Cons: Proprietary programming and hookups, not easy to repair yourself if an issue arises, modules can get pricey if you need additional add-ons
Reef Angel Pros: Flexible platform and programming language, constant R&D improving the device and addition of modules, modules are inexpensive to add, PWM and 10V dimming available, end user serviceable with electronics knowledge, non-proprietary hardware which opens the doors to expansion if you learn the platform.
Reef Angel Cons: Not as popular on the reef forums, specialized support for the specific controller, Language can take longer to learn due to it's complexity and available options
The reason why I went with the APEX was price alone. I ended up getting one used from a friend when he bought two on Ebay from a guy tearing his tank down. I personally was leaning towards the Reef Angel but I am an IT guy by trade so technology does not scare me, no matter how complex... I really liked the RA because of it's flexibility and consistent R&D paving the way for different options and expand-ability.
In the end, they both would be great controllers to have on the tank and you will not be disappointed.