As klhansen said, the engine will run at (around) the thermostat temperature, unless some part of the cooling system isn't working at 100%. Then it runs hotter. Engines don't "like to run at" a particular temperature.
No thermostat:
worse mileage
dirty oil
corrosion
extra choke use
later heat
slow warm up
Advantages: you don't have to worry about it - it's always wrong so it can't fail.
