I'm pleased to report four years of EDC with my SC600 MkII. I'm still using the original pair of Panasonic 18650's I purchased with the light. I lost the clip on the light so I purchased two more.
A previous question was "What's so great about this light?" Yes.
You know those flashlight fantasies where there's a power outage and the light cannon in your pocket saves the day? I had that experience in March at a spelling bee. There were 67 fifth through eighth graders in an interior ball room in a large building on a small Midwestern college campus. On the other side of the room was about 200 of their family and friends, including me. About 20 minutes into the bee, the entire room plunged into total darkness. About two seconds later the lights flashed one time and the room went dark again. Then a generator on the roof started and the exit signs lit up, but the lights in the room did not illuminate, obviously not being on the emergency circuits.
As the room buzzed, a few small lights pierced the darkness as people used the LEDs on their phones. A few seconds later I pulled my SC600 out of my pocket, aimed it at the ceiling, and turned it on high (500 lumens). The reaction was instantaneous. The adults on my side of the room exclaimed loudly and the kids on the other side of the room all started to laugh. I heard my 11-year-old son yell something like "My dad just got out his light saber!" The bee resumed in the darkness as the judges used cell phone lights, and I stood the SC600 on its tail on the empty chair next to me and it illuminated the peanut gallery's side of the room for the next 40 minutes or so until power was restored. It got uncomfortably hot to the touch but didn't miss a beat, and the on-board power meter suggested that I had only drained about 1/4 of the power reserves. The light off the ceiling was so bright that the woman sitting immediately to my left was knitting, and the man immediately to my right was reading a book.
The only thing I don't love about my SC600 MkII is the puke-green tint. If I ever have to or choose to replace the light, it will probably be with another SC600 but with neutral tint. A friend took delivery of an MH20 about two weeks ago and it's a fantastic light, but I'd go straight for another SC600.