I took the plastic shield off of mine when I installed it to make sure it stayed cool. It's been running like this 12 hours per day for almost 2 years now.
The best part of these lights are the bulbs being only $8 each.
I will probably build a custom hood for my tank using three of these and my other 2 NO hoods for my actinic lighting to solve the overheat thing. I have not yet noticed them getting hotter than my regular NO hoods though.