Both types are identical except for the front panel. Both provide the same amount of output and heat.
Surface temperature can vary from the bedding on the heater and which front it has. The surface is the entire plate at the front of the heater that faces the room. Surface temperature and the temperature at the top of the heater are large. Up at the top where the heat itself comes out will be much hotter and it is not recommended to touch this area when the heater is in operation.