I don't dislike the SOS function, but it would be nice if it wasn't in the mix w/ the low/med/high. If you were seriously lost or injured, I could see just leaving the SOS mode on while you were sleeping. I have the L2D Premium - 175 Lumens sure is bright! I put the L1D body on it and don't lose hardly any illumination - in fact, side by side with my brother's w/ the 2 AA body I couldn't really tell any difference when looking at both beams 200 yards out or so. Battery life will be about 1/2, but I figure I'll just carry a spare AA in my pocket or car in case mine dies. This is my first small "nice" light, but I really like Fenix so far!