I agree with much of what you wrote Backyard Brewer, but not all.
I have a peltier setup that I used to cool a fermentation chamber. I use a computer power supply to power it, and it easily outputs the proper voltage & amperage (12VDC, 6 amps). Computer power supplies must sense a load to work properly. I had to add a resistor on a 5VD output to stabilize the output (They are a "Switching" type power supply), but it wasn't difficult. Heat sinks (Aluminum fins) came with the unit I purchased. The application of the unit to the conical is indeed something that needs to be done well, but that is also true with a glycol jacket. Without good surface to surface contact neither will work well or efficiently. What you mentioned about the control of the plate is also true, but I can tell you from experience that a on/off controller (Like a Ranco) works pretty well in real life. AND, if you shut off the circulation of the glycol chiller, you will also let heat back into the system. If you consider the refrigeration system, all of the potential areas for heat transfer (Inefficiency) in a glycol system, and the power that the pump uses I'm not at all certain that a glycol system would be more efficient that a peltier system. You can easily heat your conical with a peltier system, too. That's a nice option for those who have cool brewing environments during the winter months (Or if you just want to ferment your Belgian beer at higher temperatures).
You should go fishing; it is good for the soul. Have you ever heard of a single Nazi who liked to fish? You can't trust people who don't fish. We need to teach our House & Senate members to fish. Those who don't want to should be used for bait.