I did a voltage and output test on one of these 3400K 95CRI leds, and it does not disappoint, output is better than the Yuji, voltage is lower, and it can handle more current. The max is about 22 lumen at 100mA, going higher up to 120mA gets you a bit more light for a moment but it settles back to 22 lumen again within a couple of seconds. My test rig for 5mm leds is not great, the current can not be set very well and the graph shows it, but the output numbers are correct. I also re-tested a 3200K Yuji for direct comparison. This new tested Yuji has about 1 lumen less maximum output as the one I tested before, but apart from that the voltage and output curves are pretty much the same.
Also I have been running one of the 3400K 95CRI rngwn leds all day at 100mA, and it does not seem to bother the led much, output does not degrade, steady at 22 lumen. It is not quite a 50,000 hour test but it does tell something.
Edit: there seems an effect on tint though. I should do another test for confirmation but the led seemed more yellow and when I measured it again, the duv, that was –0.0038, after 12 hours at 100mA it went to –0.0007. CRI is invariably good.
Here is the tint data at 50mA, I also measured at 5mA and that is a bit better even but only marginally
I also measured tint in the warm edge of the beam, CRI is the same but in 2800K. The CCT has some variation apparently, the first led last week measured 3320K, and now 2 leds measure both at 3200K.
(the bottom leds are two of the 3400K 95CRI leds from rngwn, top left is a Nichia GS, top right are a cold and warm Yuji)