Blower-style heaters (in my experience) put a lot of surge on your breaker and burn more electricity. My concern with your first option is the 12-hour timer - make sure it doesn't automatically turn off when you don't want it to.

I have used this very successfully: http://www.target.com/p/holmes-hoh30...&term=radiator heater

Just make sure you get a thermostat for the heater. Do not rely on the built-in one for any unit you get.