I have a double ranco and I love it. It is wired to a power strip and 5 different plugs for flexwatt are plugged into that. If you get one that is not already wired to a strip then you only need to plug the ranco into a strip and plug the strip into the wall. Then the UTH plugs go into the strip. The only odd thing I have ever noticed about mine is that the "set" temperature is 7-9 degrees lower than the desired temperature of the hot end of my enclosures. Meaning I have my ranco set at 83 but the flexwatt is staying at 90 or above. If I were to set the ranco at 90 the temps on the hot end would read over 100. I dont really understand this part but they work great for me.
What is your temperature differential set at?
Elise, I've never had any trouble from the Ranco's and I used them with UTH's on tubs...