Well, the U4 bin for the XM-L2 is the brightest bin, not commonly available. Don't think Simon has them. MtnE, Intl-outdoor, and Cutter has them - all good well know reliable source for LED's. I built 3 Yezl Y3's with them, and got 1,900 lumens measured in each.Forget the percentages, but a U3 is maybe 5% lower, than a U2 5% lower than that (T6 even lower). If you buy a XM-L2 light and they don't say, it's probably a T6, possible a U2 from a good source.
Simon is a very good reliable source for lights, but he doesn't specialize in the latest LED's.
Hang onto your 3D Mag until you’ve read some of the mod threads in the DIY sub forum. Some people love modding and some hate it. Maglites are probably the single most modded brand of lights around(says both good and bad things about them, huh?). There are at least a few members that sell dedicated heat sinks for both C and D Mags as well as some that chop single cell(14500) versions of the AA Minimag. AAA and Solitaire mods as well. Copper mcpcb’s for single and triple emitter set ups with fet drivers that supply a boatload of current. 6V and 12V emitters, high intensity emitters, dedomed emitters, spring bypasses, lighted tail caps, trits, you name it. Get your modding kit together because there’s an annual contest that brings it all together.
Bought a C8 from Simon and glad I did. What a great light for the price.
I also ordered some spare LEDs on stars. An XML came in handy when my ebay clone SK98’s counterfeit LED burned out. And it’s a LOT brighter than it was with the added genuine CREE XML LED. It is almost as far throwing as the Convoy C8. If I added stouter wires, it may throw just as far.
lumens/$ is easy if you don;t also want, small, exotic metals, programmability, fancy UI, charger built in, special tints, side switch, specific patterns [throw vs flood], no strobes in the modes, firefly/moonlight mode, memory or no memory, quick access to turbo or moonlight.,.
there are a LOT of features to pick from when you get into it……