Looks like I'm still going to use a basic one fitted for R5.
How hard do I dare to drive these?
Maximum forward current is said to be 1.5A, I happen to have some idle 1.6A 1-Mode drivers, will it spoof with them?
e: naah, too tired to fiddle, will go just one ready pill with lousy 0.8A drive.
I read 1.4 is best max
The 1.6A will be perfect. I just built one and tried to run it at 2.1 amp for turbo mode, but it maxes at 1.8A.
Riiiiight, tested. 
I'll just sum it up shortly:
- It is Cooler than my ZL SC51w. Cooler and "cleaner", I would say.
- It has no bluish hue, like my XM-L 3C dropin from Intl O.
- It has very little, of ANY annoying hues, whatsoever. No green, no blue, no purple. Perhaps there is some yellow but mainly, it is just white light.
5 / 5, easy.
Aaah, OK. Must change the driver at some point.
Now testing only at 0.65A but the output seems pretty much what it should.
But What A LED!!! This + Zebralight = !!! :D
The one I got looked identical to the 4B tint R4 XPG that KD sells. I honestly don't know what all the hype is about.
I recall testing 4B R4 also but cannot do side-by-side now.
Somehow I feel it was a bit warmer but as said, cannot be sure now at all.
I have a couple KD R4 4B tints on my torches, and side by side, the Nichia wins hands down on CRI, Tint however is not bad between the two. The 4B is closer to daylight (indoors) a little warmer than daylight, and a little on the green side, the nichia is also very close, but definitely warmer and slightly on the red/pink side. Both are the closest tints I have to daylight. (comparing to 5B, 5C, 3C, 5D, and about 2-4 LEDs of each) Right now its 2pm and I face south (away from the sun).
The colours of the Nicha are superior to the 4B which has a greenish wash in comparison.
First I want to say I was little skeptical about the whole high color rendition index LEDS, I thought it was a joke. Anyways I took some brightly colored shirts and laid them out in a dark room and grabbed a bunch of my favorite tinted lights and........................................... well OK they all vary with the Nichia being the clearest. The description of a lightly fogged up lens on your glasses while looking at the non CRI lights is exactly what I saw. The 3DXPG in particular was very close to the Nichia in color rendition but they are no longer available. So I guess I will be building a couple more of these so I can keep one for myself.
Some beam shots against some of my favorites
3D XPG Nichia 219 4BXPG
4B XPG 4C XPG Nichia 219
7B XML 4C XPG Nichia 219
Thanks for the tint comparisons E1320. It gives a nice idea of how they look.
Where did you get the 7B XML? It's very warm. Is it a T6, T5, T4...?
The 7B is a T4 I got them from LCKLED, I did not like them at first but now it's one of my favorites. It's the same tint as the setting sun through my bedroom window.
http://www.lck-led.com/cree-xlamp-cool-warm-white-leds-w16mm-board-p-924.html?cPath=37_107
I finally got around to using my Nichia I bought from Craig. I put it into a new TR-801 I recently received. Wow! The color is beautiful! Might not be the brightest light I have but immensely useful and with great run-time from an 18650 in a pocketable light. Perfect dog-walking light for sure! If you haven't tried one of these 219's yet, do yourself a favor, pick one up and put it in something. You won't regret it!