Yes, many people here (including myself) use it. It takes a little bit of tweaking to get it stabilized, but it works wonders. It's perfect for small-collection herp keepers to regulate one enclosure's heating devices. I would recommend getting a Lutron 300W lamp dimmer as a backup in case the tstat ever fails (can happen to even the best tstats).
Plug the UTH into the dimmer and set it to about 95 degrees. Once that stabilizes, plug the whole UTH/dimmer assembly into the 500r, then set the dial on the tstat. And you're done.
The probe for the tstat should be put in between the UTH and the bottom of the outside of the enclosure.
I have my probe inside the tank under are the substrate against the glass.
I can unpeel my UTH ? It won't stay on.
Works pretty good for me. It ranging from about 89 to 92 degrees which is Great I think. 500r is cheap and good.
1.1 Normal BP
0.1 Broad-Headed Skink
0.0.1 Bearded Dragon