You get energy consumption less than a fluorescent, and far less than an incandescent. You get extremely long life, on the order of 20,000 hours. And many are dimmable.
There are LED downlights that surface mount to a j-box that will save you the price of a can and trim. I just bought some that are dimmable for $37 each. There are also LED retrofits for popular cans if you decide to forgo LED initially but might want to change later on.
With any lighting it is good to consider color temperature. Some environments look better on the warmer end, some on the cooler end. Most household light is on the warm end. Even the "cool whites" are only a little cooler than incandescents, nothing like daylight or studio lights.
FWIW LEDs do put out heat, just not as much for the same amount of light. That is why they are more efficient. The amount of heat generated will be a little less than the equivalent CFL.