I like that the RA is open-sourced, whoch will allow me to write my own code and give me the power to govern my controller. I dont like that its not considered plug and play. From what i can tell, it takes a few months to get it nailed down right. Also with the RA, i get pwm to control the intensity and duration of my powerheads (controllable ones) but i have to buy an add-on for the internet capability. In the same sense, the Apex unit comes with internet connectivity, but needs another module (vdm) to give me pwm control of my powerheads. Also, i absolutely love the digital control pad of the apex and its small size. The apex is also considered plug and play in that all i really need to do is hook up the hardware, calibrate the necessary probes, and setup the desktop screen... Thats it.