I've used the E05, iTP A3, Eiger, and LD05.
The brightest are the A3, Eiger, and LD05 when using a 14500 battery. The Eiger has a really wide spill, and the A3 and LD05 have a much better hotspot and look better for an 'overall/everyday' keychain light, IMO.
Between the A3 and the LD05, I...