> Is floatation important?
The three issues I find with modern retroreflective aimers are:
(1) The brightness of the "fireball". Some are too bright in full sunlight (which I address by using sunglasses), and some are too dim in dim sunlight. This is a long recognized problem ( see this patent:
http://www.google.com/patents?id=ys1DAAAAEBAJ ). Of the modern mirrors, I find the Starflash too bright, Rescue Flash, Coghlan's and Vector I brighter than I favor, the one Rescue Reflector I have a bit brighter, the 3"x5" S.I. Howard mirror aimer is "just right" and the 2"x3" S.I. Howard mirror on the dim side.