I have two M6s, both used as emergency lights, one in my car and the other in my RV which is heavily used by my parents. Both have the HOLA installed.
Both are intended for specific purposes where the short burn time is not problematic: signaling at long distances (SOS) and scanning treelines and such at a distance.
Each vehicle has an SC2 battery carrier with the LOLA and six spare batteries. There is also a Z3/KL3 which is intended as the primary light for any emergency in or at the vehicle. The M6 is in the trunk and Z3/KL3 in the center console or glove compartment.
Of course, I never leave the house without an ARC LS in my pocket.
The idea is that the Z3/KL3 (or my ARC LS) will deal with almost any flat tire or other problem and hold out until morning if needs be. But it does not have throw. The M6 provides throw but isn't useful as a general-purpose emergency due to the lack of burn time.
I'll probably replace the Z3/KL3 lights with small 5W lithium lights this year, even if it means having to carry more $$$ lithium batteries – the 5W really is a lot brighter. But the M6 will probably retain the role as the brightest, longest-throw lithium light.
The RV typically carries several other lights and I have TigerLights at home and at the cottage – there isn't usually much need to use the M6 with its expensive and short burn. But in the emergency role I have for it – a really bright emergency light that is sure to work five years from now when I need it – I don't know of anything better.
As for an M9: The Surefire catalog shows the B1 will have 2000 lumen and a burn time of 80 minutes, and will use (20) twenty batteries. The price is not given...
