I think the RKE is a good controller.....the apex is also a good one. I think the biggest question is what are you going to use them to control? If limited control, you might be able to get away with a cheaper version.
As far as the lifereef skimmers......I ran one for a while and they work great. The biggest thing about them is their simple design and small footprint. I just upgraded mine. I had the SVS2-24 in-sump 22 1/2" tall.......which is now for sale if you were looking to buy one......soaking in vinegar as we speak