I bought the SST-50 in late March this year and love it. I have had it on about 13 night dives and have had no problems.
I would not trust the setting where it tells you the charge of the battery by the number of blinks, it always seems to say it is fully charged. I would also say to fully charge it between dives. I usually run mine on the low setting kicking out and the highest setting during the dive. I tried to get 2 dives out of one charge once. The first dive was fine, but the 2nd dive a few days later did not go so well. About 3/4 through the dive the light just shut off.
I found out the hard way that the batteries have a protection circuit that shuts them down when the voltage gets low. No warning at all, straight to darkness. After that I do a full charge before each night dive, which is about once a week.
I normally put the batteries in the light as I am getting ready to dive. I heard somewhere that even though the light is off, there is a small drain from the circuitry in the light. To turn it on you have to rotate the silver ring around the head of the light. But since I do not store it with the batteries in it I don't have a problem.
I just had a friend buy the MC-E, but I have not had a chance to play with it yet.
Do a search in the light forum for:
SST50
magicshine
mj850
That should get you a few threads to look at.
