I have a couple of LOD-CE's. Once I tried it on 3.7v LiR's, I dont think I could ever go back. All the brightness setting work great, the output is excellent. It does get warm when left on 'Hi', but it's not a big deal. I left one on high and set it down for light while I was working for around 5mins, and it felt hot, but didn't feel hot enough to worry about anything. This was in a cooled datacenter with lots of 70deg airflow, perhaps in warmer enviroment it would become a problem.
To give you an idea when I compare them, the low setting on the unit with LiR seems to be about the same intensity as the high setting with a NiMH AAA cell.
The low and medium settings work perfectly with no real temperature raises noticed on the light, but huge light output increases vs NiMH.
I often here people who haven't actually tried it themselves saying that the unit gets too hot in a few seconds etc. I know everyone has a different line they draw between warm and hot, and hot and danger, as these are all value based words. After useing it for a couple weeks on LiR's, I place it at the HOT term, but not the danger term. The more an objects temperature rises vs the enviroment around it, the better ability that object has to transfer energy away from it and into its enviroment. If you reach this thermal equilibrium at a temperature below a damage point for the battery, LED, or electronics, why should it be a concern?