I have no knowledge of other controllers at all but - I just got the RKE W/NET and it is pretty cool. email alerts, data logging, RSS feeds, web page server to log into when you are away from home and want to check up on things. Right now you cant control the unit remotely but is supposedly in developement for a future firmware release..i measure PH, Salinity, Temp, 2 Koralia 4's on a wavemaker setting, lighting, fans, sump, skimmer etc..
you can set rules to take action on things while you are away (or on your couch..hehe) i have mine set to turn a fan on if the temp hits 80, if it hits 82 the lights will turn off and turns on another fan etc...
I will say the programming and set up (dont know about the others) was kind of daunting, once i got the hang of it its really easy.
Getting the NET module was a bit of a pain to get running as i was trying to use a wireless access point to get it online...no go, people have set them up wireless with devices but i failed every attempt. i just hardwired it with an ethernet cable and it works like a champ..
warranty - 1 yr but Digital Aquatics basically says - as long as you have the receipt and its not normal wear and tear, and you didnt damage it - they will cover it.
Tim at Keen Reef sells them for $417, cheaper than online from Digital Aquatics..or Marine Depot
good luck in whatever you choose