Radiant heat below flooring is supposed to be awesome. I think Judi has it, but she hasn’t been on fluther lately. If I lived in a cold climate I would definitely consider it. Heat rises, so heat from flooring will help heat the room well. Plus, having warm feet is always a plus in the winter months.
Radiant heat through pipes, like what you find in NYC apartments, can make a room unevenly heated if the room is large, but usually if they are sending up a lot of heat you don’t notice it, in fact sometimes you need to crack a window the room gets so toasty. It depends on the building.