Thought this would be an interesting comparison since a casual glance suggests the three lights have similar outputs and beams.
L1D-CE (arrived today)
This is about the smallest light that I can comfortably hold and use. Ideal EDC IMO.
This is my first experience with a reverse clicky so I hate it on principle (nothing happens when I press), but it is an important part of the UI. Personally I really like the choice of modes and switching sequence, except the SOS really bugs me since I end up in it by accident all the time. I'm hoping SOS has a really long runtime to justify its existence -- I'll leave it running overnight on a fresh alkaline to see what happens.
Normally the light will be set to switch on in "low", which is all I need most of the time, but outside it's really nice to be able to go up to "high" and get a big flood of light. Not sure if "medium" adds anything yet, will try a night hike and see if maybe that is its niche.
The hotspot is wider than either the Scorpion or the MagLED, and more useful than either of those for indoor use. Brightness is pretty consistent across the hotspot (kinda like the Mag, although the Mag has a much smaller hotspot) while the Scorpion LED has a bright hotspot fading smoothly to the spill beam.
There are obvious dark rings in the L1D-CE beam when shining on a wall, although you don't reall notice them in normal use.
A couple of times I managed to get the light into a wierd state. I would start in low, with the normal "bright flash" as the light came on (sort of the opposite of a soft start, I guess ). Each time I hit the momentary off to switch modes, the light would flash brightly but immediately fade to low again. Twisting the cap to "max" and back would eliminate the problem. I suspect this may have had something to do with having the cap twisted "very close" to max mode, since it never happened if I had the cap twisted at least a half turn away from "max".
Overall I really like this light. The switch makes a bit of a scrapy noise when turning on but that will probably go away with use. Low mode is what I expect to use 90% of the time but I really feel more comfortable having the extra bright output on tap for when it's needed. It's tempting to say "we only really need low and high" but I do expect to have some fun with the strobe.
SL Scorpion LED
I sort of bought this by accident -- thought I was ordering an incandescent Scorpion but this showed up instead. It's not as bright as the incandescent (42 lumens rated) but the beam shape is great for medium-range outdoor use. The tint is noticeably cyan-coloured compared to the L1D's Cree.
When I shine the L1D-CE out my front door at the road 200-odd feet away it lights up the area nicely but doesn't really let me see wolves and coyotes on the road waiting for deer and little dogs. The Scorpion has a smaller beam with a bright center section to the hotspot and lets me see much more clearly out by the road, but still not clearly enough. The MagLED 2D is pretty much the minimum I need before letting the dogs out at night, and normally I grab the MagCharger/1160 which lights up the road very nicely.
This light seems to be at its best when searching a dark house or office. I haven't found a better "small light" yet -- the Scorpion LED is noticeably better than a P60-based Surefire (eg. my Z2) for example. I think it's because the beam fades more smoothly from the center to the edge, resulting in the ability to see clearly over a wider area, but that's just a guess for now.
EDIT -- after some more tests, I now believe the difference is that the SL has a smaller spill beam but the average brightness is higher. The result is that for me the spill beam on the SL is "bright enough for me to see" while the spill beam on the Z2 with P60 was wider but not quite bright enough.
I switched the L1D-CE "SOS" off -- it was just too annoying even with the light locked in a closet -- and took it through the same "basement clearing" exercise. The L1D-CE gave me a more comfortable feeling than the SL Scorpion LED at most distances due to the wider, more even hotspot, but the SL was much preferable when dealing with a wide range of distances, eg. an open utility room door 40 feet away where most of the walls are 10-20 feet away. The "brighter in the center" hotspot of the SL was much more effective than the "wide, even" hotspot of the Fenix for lighting up the inside of the utility room from a distance.
This has the stock smooth reflector and so is a totally different animal from either of the previous two lights. The hotspot is very small and quite a bit brighter than even the L1D-CE on max with a fresh cell. The light is not ideal for indoor use unless you defocus and live with the rings, but for spotting outdoors it's noticeably better than either the L1D-CE or the SL.
The beam is a bit blue compared to the Fenix, or you could say the Fenix is a bit green compared to the Mag.
I'm still think the MagLED was a huge step forward for Mag, although IMO they aren't promoting it well enough to really reap the benefits. All it needs is a slightly textured reflector (with a big hole ) to make it great.
The Mag was not as good at "basement clearing" as the SL or Fenix. The central spot is really bright and the spill beam is large and not very bright. Defocusing helps a bit but it really needs a slight reflector texture. It seems to put out a bit more light than the SL so I think the throw would still be OK.
Playing with reverse clickies for a couple of hours hasn't really made me like them any more. I guess the perfect light for me would really be a Surefire L1 with a Cree or P4 LED. Big surprise there
So far I'm only really finding a use for low and high, although SOS is so darned hard to ignore that I'm sure it would be useful if I needed help. I don't think many people would recognize SOS in these unenlightened times though...
I haven't figured out if the L1D form factor (typical AA light) is the ideal size compromise or the worst compromise (too small to hold properly, too big to fit in some clothing). I'm 6-4 with zero-to-negative fashion sense so for me it seems like a pretty good EDC'er.
The key thing, however, is that this light gets a LOT of useful brightness out of a common AA alkaline. Chevro's runtime graphs make it clear that alkalines are most viable if you are using on low most of the time, but I can live with that. I expect I will end up using this with NiMH anyways.