Ok, I added S4, S5, and S6 to it.
"For XM-Ls the brightness bins range from S4 (which is the least efficient) to U3 which is the most efficient. The order is S4, S5, S6, T2, T3, T4, T5, T6, U2, then U3. Most lights are a T6 bin unless otherwise specified."
There is not a S3 as that is not one of the bins available for XM-Ls if you consult the datasheet.
http://www.cree.com/~/media/Files/Cree/LED%20Components%20and%20Modules/XLamp/Data%20and%20Binning/XLampXML.pdf
Yes, the S2 and S3 are only present for the new XM-L2 http://www.cree.com/~/media/Files/Cree/LED%20Components%20and%20Modules/XLamp/Data%20and%20Binning/XLampXMBL.pdf
You could mention that "5" is specified as being Neutral White in CREE datasheets.
Nichia for example says White and WarmWhite for the 219 series. For them some Neutral Whites (5000K) are simply Whites, and below that they are all Warm Whites.
Ok, I added this.
"Note: Going off the the Cree datasheets 5 is NW, but I find it to be much wamer than neutral."
You’re quite right!
It makes very good sense of Cree to subdivide the bin boxes at the lower Kelvin temperatures.
The perception of the color shift between two temperatures is not proportional to the Kelvin temperature but to the reciprocal temperature. See the MIRED scale here.
So perceptionwise the 1A box is quite small and the 5C1 box is quite big.
Scaru (or anyone else that knows) - I've been trying to figure this out, but simply can't do it:
From a CREE part #, can you tell if it's exactly 1A, 1C, 3A, 3C, etc.? The part #'s in question are XM-L2's:
XMLBWT-00-0000-0000U20E1, XMLBWT-02-0000-000LT60E3.
What I can tell:
XMLBWT-00-0000-0000U20E1 - 6500K, 65 CRI (on mouser.com)
XMLBWT-02-0000-000LT60E3 - 5000K, 75 CRI (on mouser.com)
The E1 and E3 are kits #'s, where E1 includes 1A, 1B, 1C and 1D, and E3 includes 3A, 3B, 3C and 3D (all from the CREE data sheet: CREE Xlamp Xm-l LEDS). So if the kit #'s can't point you to the exact tint, what would? Or do you simply have to take your chances?
Ohh! Forgot to mention: Thank You scaru!! This post is very informative!!
I think those are "order codes" and you might need the "bin codes". Page 2 of the XML Binning & Labeling guide shows the difference.
To see an example of a Cree "bin code" in real life, check out the package in this photo.
Ok, yes i saw those too but that info doesn't seem to be provided by Mouser. Those order codes are called the manufacturer part # by Mouser, so, still unknown what you are ordering?
Sadly, I think that is true. One can get a general idea from the bin, but nothing conclusive. E.g. it is a U2 you know it is CW.
That could be worth a shot.
Turns out he deleted the comment after I hit the quote button. ;)
Lol Scaru, I think that post of mine was up for all of 30 seconds.
Here is my revised response:
Some sellers know the bin code and will tell you if you ask. If the sales rep doesn't have that info handy, someone in the warehouse should know. If they sell individual stars, the bin code is usually printed on the back of the star. If they sell by the reel, the bin code is usually printed on the reel.
Having said that, I've never tried calling Mouser, so I don't know if that's something they would do. Same goes for Digikey.
Sorry. :P
I got 3 of the XM-L2 T6's, installed one today in a C8 pill - not too bad, similar to a 3C tint. But definitely would prefer the U2's, and now the U2's are showing in stock and the T6's are out of stock. The XML2 T6 seems to work ok, even though I originally put it in backwards - duhh, wish it was brighter though. Wonder if I did some damage - in theory I should be getting 3.77A but measuring only 3.6A. The U3 1C still seems to be brighter on a simple ceiling bounce test - the U3 1C is 3.8A bu design and measures 3.8A exactly. So, I should order a few XML2 U2's but for $7.37 plus shipping, not a great deal. I'm thinkin I may destroy some of the stars when removing them, so may need some blank stars but can't locate any, not even aluminum, forget about copper...
Hhhmmm, may be off topic here with that info.... Still Mouser and Digikey are the two main sources to get the CREE LEDs bare, and you can't tell what tint you are buying? Weird...
They list the tint - ie 3000K, 4000K, 5000K. Just not the tint bin - ie 7A vs 7B, 5A vs 5C, 3D vs 3C, etc.
My limited general understanding of this subject is that daylight is broad spectrum light but LEDs are binned based on the dominant wavelength and also has other peaks as well as missing wavelengths. Does hi-cri mean that the led has a better broad spectrum output(fewer gaps) with the penalty being lower overall output?
Thanks! 
Yes, it contains a much broader spectrum. If you look at the spectrum of the Nichia 219 (H1) it is much broader than the one of a XP-G. (See Below)
As you can tell, the Nichia 219 is superior in that way. Also one can see why the 2600k XP-G is higher CRI than the 5000k XP-G.
talking to Craig Shih from Illumination Supply about it and he said it’s just a roll of the die which tint you’ll get within a given kit no. One of the downsides of ordering bare LEDs from Mouser/ Digikey. Still, from what I’ve heard, all of the 3* tints are pretty nice.
Great information here! Thanks a lot for compiling and sharing it. Sticky’d.
+1
Thanks Scaru.
I bought 2 of this type from mouser, they are out. The do have the XM-L2 U2 6000K CW:
http://ca.mouser.com/Search/ProductDetail.aspx?qs=5YqktSXERipfLuRE%252bJbsug%3D%3D