I bought the original MTE 5 mode way back when and have not found a better cheap P7 light since.
I also have received an Elektrolumens M@g 3C-P7 and have an Elektrolumens EDC-P7 on order but those are in the $150 range.
18650 batteries range from 1200 mAH to 2200 mAh actual. With most of the older lights running at 2.2 A on max and a few of the new ones up to 2.8A the runtime is 1/2 hour up to just under 1 hour on max. CAREFUL ABOUT YOUR SELECTION OF BATTERY.
I would get a multimode that has a medium mode. Light output does not drop by much but doubles the runtime. And the light does not get too hot to hold. Max is always there when I need it.
Or you can get a 2*18650 if you do not mind the bigger size.
Until about a month ago quality has been adequate. There was only 1 report of a DOA light. The UI of the 5 modes tend to be finicky.
Unfortunately with more and more models coming out the CRAP is starting to appear. For example with this one:
http://www.dealextreme.com/details.dx/sku.14741
1st customer review "had to fiddle with the light to make it work the first time"
2nd customer review "To correct the pill, heat the pill a little and take LED apart from pill and re-epoxy the LED to the pill. + other fixes needed."
3rd customer review "poor quality of the pill, no heat conduction; Pill was loose not fully screwed in the body"
It is now buyer beware time. Read the reviews here and on the DX site carefully looking for LACK OF PROBLEMS before you buy.