The Inova Microlight is the single least satisfactory flashlight purchase I have made. When I carried it in my pocket on my keychain it turned itself on EVERY time it was in my pocket - I know because it had changed from momentary to constant on EVERY time. The LED was loose in its socket and required me to dismantle it and tweak the leads weekly to get it to stay on - at least a third of the time when I turned it on it either flashed off immediately or required me to move the LED around to get it to turn on at all. The loose LED is probably the only reason the battery didn't get used up in the month I carried it daily, an example of two wrongs making a right. The POS is now in a drawer.
Best keychain lights:
Fenix L0P - brightest and most useful beam
ARC AAA-P - bombproof, long run time
Lighthound/Emilion "Fauxton" - best cost and size efficiency
I currently carry a Fenix L0P on my keychain, with a Lighthound Fauxton as a backup.
EDIT: My ARC AAA-P finally arrived. Wow, what a beatiful tool. It went on my keychain for a day, replacing the L0P as a trial. The ARC is staying. The size difference is VERY noticeable to me. I didn't weigh it, but I think the ARC with an alkaline battery is lighter than the L0P with a lithium. Transferred the lithium over to the ARC, making it a little brighter and super lightweight.
Therefore, my strong vote: BEST keychain light : ARC AAA-P
I still like the L0P alot. It is going on my "small tool ring" with the Victorinox Minichamp and Colibri butane torch lighter and some other small tools that I carry often.
My opinion: Every flashaholic should own at least one Fenix product and one ARC product. I think I need a Peak product next....