After not getting any responses here or on several other reef websites' forums I decided to take a risk and buy the unit without the optional controller. What follows is a brief review.
I was having a problem with heat on my 10g nano because of the 96w PC lighting I have over it. The temperature would fluctuate during a 24-hour period from 78.1 just before the light turns on to 82.9 at night just before the light turns off. Since the tank sits in my family room, I didn't want a loud and bulky chiller sitting out for everone to hear and see.
I purchased the Microchiller from MarineDepot.com. Actually, I purchased the unit that was already drilled into the top of a hang-on-the-tank style filter. If I had to sum up my experience with the unit in one word, that word would be "FANTASTIC!"
The chiller has far exceeded my expectations. It was a snap to set up. Literally, "plug and play." Hang the filter box from the back of the tank, fill it with water, plug it in, and that's it.
The fan noise? Virtually non-existant.
The results? I run the chiller on the same time cycle as my light. 11 hours per day. My temp now fluctuates from 76.5 while the lights are on to 77.1 while the lights and chiller are off.
Since I've only had the chiller for less than a week, I can't comment on it's long term durability.
Based on my limited experience so far, I would definitely recommend this unit for nano applications.