To answer the question, LEDs are more intrinsically efficient than fluorescents, by probably about 20-30%.
So if you're looking at a certain amount of light output, LEDs should be able to get you there with less power draw, and therefore run cooler. If the LED panel is designed right, LEDs also have a potential advantage of more specifically tailored spectrum, meaning less light is "wasted" in spectra that plants can't readily use. Again, a way of saving energy, and therefore creating less waste heat.
But the fact is, neither LEDs nor fluorescents are all that efficient in converting electricity to light.
BOTH of them will ultimately convert MOST of the electricity they draw into waste heat. If you are running 200-300 actual watts of ANY light in a small cabinet, be it CFL, LED or HID, its going to get hot, period.
Next issue is that LEDs generally don't really draw the energy they're rated at; they're specifically designed to run at less than full wattage in order to run cooler and preserve diode life. For example, the so-called "Blackstar 240" actually only draws 130 watts, and the same is true of most of the LEDs on the market.
So of course the (so-called) 240 watt LED is going to run cooler than 10 23 watt CFL bulbs. . .the LED is only drawing 55% of the energy!