Re: Trying to decide between a SF M6 or 10X
I wouldn't get either light, based on your initial requirements. The M6 is a wonderful light, but it eats up lithium batteries at an incredible rate -- maybe $20 to $30 an hour. I had a 10X and didn't like it. I don't like NiCads, either, as has been mentioned. It does have a nice low beam -- either 60 or 110 lumens -- and a 500-lumen-plus on high. But if you use the low beam for any period, the high beam very quickly runs out. Plus, neither of these lights is regulated, so they start to dim immediately.
If you need 2 hours of runtime, you may want a high-output LED or an HID. For night hikes, you may want the option of a much dimmer beam, so a multiple-brightness beam would be best. With $400 to spend, you have a lot of great options. Check out Custom B/S/T and read what Milkyspit is doing. That will give you some ideas.