I have a helix and a johsons control. Both are great. I love my helix, my johnsons works very well (but I can hear the click when it powers on and off). I've got a dimmer switch on my bearded dragon cage.
I will either be getting another helix or a herpstat when I find the need for more. If its just a basic rack I may get another johnsons unit. They are reliable and Rich at reptilebasics takes customer satisfaction seriously, i thought I had a malfunctioning unit like 6 months after I bought it and I shipped it back to him and he replaced the power strip on it for me.