Okay, everyone’s gonna dogpile on me for saying this, but I don’t have an A6. I keep hearing it’s a great light, and I’ll leave it to the choir to preach about it. 
That said, the ones mentioned kick arse.
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The S2+ is the de facto first-light everyone should get, but DO NOT DO NOT DO NOT get the ones with the 3/5 modes, because the blink-on-low will make you want to launch it into space, or at least fling it against a very hard wall. It downright pisses me off.
But it’s easily moddable. You can get a shorty tube and use an 18350, and switch back on a whim if you want longer runtime of an 18650. It takes 20mm TIR lenses so easily and smooths out the beam and virtually eliminates any fried-egginess (yellow-white hotspot, blue-white spill). Standard 17mm drivers will drop right in, you can swap emitters ’til you puke, add a lighted switch, whatever floats yer boat.
The new colors, orange and purple (and teal, but ain’t got), in addition to red, blue, green, gray, the other gray, the other other gray that’s almost black, clear/silver, etc., all let you go crazy.
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The F1 is probably the best-thought-out light I’ve seen in a loooooong time. Love the tailswitch for on/off, and sideswitch for mode-changes. Blinkies are nicely hidden, difficult if not impossible to get to accidentally. You can almost forget they’re there. The usb-port is covered by the screw-ring, not a dinky rubber flap. The short-travel tailswitch is nice and crisp, which I like, but some people don’t.
My only grex? The greening of the beam thanks to the AR-coated glass. With clear uncoated glass, the tint would be pretty good. NW is worse than CW, ironically enough.
Other than that, I love it.
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Alas, the Sofirn SP32v2 deserves mention. Take an S2+, make it a side-clicky only, throw in a r/y/g battery-level indicator in the switch, use a DTP-mounted LED with temp control and squeeze out a bunch more lemons, also throw in a pretty decent ramping option in addition to stepped modes, and you got the v2. Plus, it comes in “pale gold” (infinitely hard to describe, but quite nice) and silver (still in transit), and you got a really sharp-looking light.
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Honorable mention goes to the Nitefox UT20. I still edc that with the S2+ deep-carry clip which fits and looks as if it were designed for the light. Also has a battery-level indicator in the sideswitch, the tailswitch is a forward-clicky!, so you can do momentary-on. Has usb charging as well. It’s a monster, longer’n even an S2+, but with the deep-carry clip, I couldn’t care less, as it rides nice’n’low in my pocket.
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There are a whole bunch of other lights like the TK18 (ramping+stepped tubelight), which are also quite nice, but damn, the field’s gotten really crowded the past coupla years.
Just a few years before, if you didn’t want to pay big bux for a Streamlight, Suefire, etc., you were pretty much limited to a ’501, ’502, or zoomies like the ’68 or ’98, or real craplights that, believe me, you didn’t want.
Hell, my first “good” light was a discontinued Quark 2AA-X for 80bux each! Performance is about on-par with the 15buk Sofirn SF13, minus the really nice twisty-switch for instant-turbo.
My advice? Get at least 1 of each of the above, then decide for yourself. :))
Sooner or later, you will, anyway, so just save yourself the angst.