For me I don't like small aaa lights that have different body diameters. Some small AAA lights have larger reflectors that require different diameters to compensate for the larger reflector and also for the electronics. Its done to eliminate having to design an efficient small relfector and the difficult task of having to shrink the electronics. It is easier to make that part of the light larger to fit everything.
The Revo head is not any larger than the very slim body -as slim as possible for the AAA cell. This is a pretty difficult task. The driver is also constant current regulated rather than pulse width modulated. This eliminates any possible stobe effect.