Depending on how much wattage you are pushing through them the hope depot ones and the like are fine. They claim to be rated pretty high on watts, but once I started pushing 1000+ watts through them I was burning them out in months. While spendy, I ended up with an RKE, mostly for lighting (I'm controling lights on 4 tanks admittedly), and have really enjoyed a bunch of the features I never thought I would use or need on them. By the time you have gone though 5-6 cheap timers (which work just fine really) you could add temp, salinity and PH monitering plus the ability to shut of return pumps for feeding and stuff like that. If you know someone local to you that has someththing like the reef keeper light or the like, it might be worth checking out what it can do. Granted not many have an extra $100 kicking around but its a thought.
In the scheme of $$$ we tend to put in to these tanks,