Hey! I haven't posted here in AGES, but I've had the E05 on my keys for a LONG time. I don't remember when I got it, but they had just come out. I'd never seen or heard of it at the time. I paid 15 bucks at the gun store ( a friend owns it and sells to me cheap because I'm the one who convinced him to carry Fenix products).
After at least a year, it's holding up well. Only on the second battery, I think. Same hard coating as the LD01, so it's not chiped ot scratched much at all. And I've dropped it tons of times!
Oh, and there's no leverage on the threads due to the short LED module, so it won't come on in your pocket as easily as the LD01. The threads/o-rings are more snug as well, so it won't twist on by accident. It just feels tighter and more durable than any of my LD01 lights. I could swear that the housing is thicker, but I know it's not. I'm not sure why it feels more heavy-duty. It just does.
For working on small stuff like computers, this beam is amazing. It doesn't have much of a hot spot, so not too much light reflects back at me, which is a good thing. The brightness is just right. And that funky lens makes the light incredibly smooth and evenly distributed.
The only downside is that it doesn't throw far AT ALL. Beyond just a few feet it's useless. But keychain lights aren't for throwing anyway.
Oh, and lastly, I'm 99% certain that mine has a Q5 LED, but I think the ones they are making lately have an R2, so your results may be different than mine.
Probably my most useful light!
oo: The plastic lens was overheating. IOW, my nice new E05 was fried - and tossed. 
