I'm running a home made 1W lux "bulb" in a PT40 at full current, and even though it gets quite hot during use (too hot to touch), I have run it for extended periods several times (once more than an hour). It seems no worse for the wear after a lot of use. The "bulb" is simply a PR size metal slug with an appropriate resistor calculated to give me 350mA at 4x1.2V (NiMh), so it is actually slightly over-driven when the batteries are fresh off the charger (1.3-1.4V).
I thought the EverLED would be the lazy way to get regulation into my PT40, but the Ever is quite under-driven and doesn't even come close to my home made hack-job. Of course it also runs much cooler. Compared to the stock PT40 lamp, I'd say it's pretty close. It's much whiter in color, and has a larger hot spot with a bit less throw. There is also one ring around the central hot spot (which I don't have with my home made hack).
Compared to my home-made 1W Lux or a good Xenon replacement lamp, the EverLED will be dissappointing. And there is the very real risk of smoking the EveLED since the PT40 can take batteries either way. If you are careful, though, the EverLED will produce a nice, bright, white light from the PT40 that will run for a very long time on a set of batteries, and won't change in color or brightness when switching between disposable & rechargeable batteries.
Aloha, iG