They are all relay and can be used to control anything, i'll be getting a 2nd relay box to be able to control everything in my tank from the controller.
RA is a bit tricky to change things, cause you need to code it, but the community and Roberto itself are great, i have never had any experience programming or doing anything like this i have been able to do everything i want with my controller and more, i'm sure the other brands of controller are capable of doing it, but for the price and how easy is the access to support is a no brainer for me, if i have to chose a controller again i chose RA.
Another plus at least for now is that if you need an expansion and is not available you can ask Roberto, if there are several people that want it, he might build it, if not he might help you build it.