Doni asked to chime in
I have owned all 3 of the RK products the RK, RKII and used them for over 3 yrs and loved them and never had a problem with them. They pretty much controlled every aspect of my tank except the ATO and PH control as I have separate controllers for that.
When I set up my 210g I admit I had to have the new toy the RKE to go along with it and after having the others I admit it was a little intimidating using it at first. In fact I actually kept one of my RKIIs on my 210g running some stuff till I hooked the Elite up and knew it was programmed right. There was a lot more menus and programing options to get into that were not there before. You also had to "Turn On" every plug before they could be used in the menus and then set them all up which was new. I was used to just saying make it a light or a pump or this and bam it did it. The RKE had many more options to choose from and what you wanted it to do first before using that actual plug. There were some issues with first software issues with the unit but none of the problems effected anything on my tank but you will want to flash yours to the 1.07 update anyway.
Once I got mine all set up and really learned how to use it I really was glad I bought it. It really has a bunch more capabilities over the old units, the abilities to warn you if something goes out of whack with settable alarms, graphing, controllers, can control way more items just by daisy chaining PC4s and other items. You can change the display to show you any of the units many items it is monitoring as well as the current condition of any of the individual plugs on the PC4. Its a very informative unit over the older ones and very upgradeable over the older ones. You can add modules to add new things as you like from DA as they become available in the future
You will like it once you get it controlling the tank.
I even framed mine