The keychain light you refer to is the AAA aluminium light? I have a couple, not fantastic finish,some of the edges are a bit sharp, tiny hole for lanyard,do not trust the keychain it comes with, cheap...but you know what? I kind of like it, not as bright as an infinity ultra but brighter than arcAAA V1 (reputedly) and also a gerber recon and a cmg infinity, and it's so cheap you can just sling it anywhere and not worry about it (not like your Peaks, Arcs, Fenixes, INOVAs etc).
I prefer it to the SONIC and it seems a bit more reliable (though I wouldn't trust my life to it!!)
Get a couple and have a laugh...:lolsign: