Maybe someone can do a proper review for the C01 (not me) with runtimes and abuse tests.
BLF discounted price is $6.50 each
OK, just got notification that the price was adjusted.
This time all went fine and I was able to pay.
$6.50 … Yeah, I like the 5600K much better myself. The 3200K is much to orange to suit me.
I’m with jon_slider - which I prefer is highly context dependent. When I’m using the Yuji’s in my home after dark, the 3200K is perfect. I’m sure it will be nice around a campfire, too. In other contexts, though, the 5600K suits my need better.
@joechina, AAA lithium primaries like the Energizer L91 will always last longer than alkaline and NiMH cells, except in cases where the power draw is very high, like in a Zebralight SC5W.
I waited the price adjustment out. Took a little over 3 hours. Got em for $6.50 finally… 
Yeah, I don’t think there is a right or wrong on the tint… just individual preference.
In the pitch black of night in my home the 3200K just does not cut it for me as a preference. It just doesn’t have a natural look to me as it makes everything have an orange tint. Nothing wrong with that if that is what one likes, I am just not one of those people. 
To each of us his own……
Yep, same here.
when I see 5600k as “natural” and 3200k as “orange”, my brain has been white balanced to 5600k
when I see 5600k as “glaring” and 3200k as “natural”, my brain has been white balanced to full darkness, for at least 1 hour…
I see 3200k as orange during the day, but when I wake in the dark for a bathroom, the 3200k is much more pleasant, and does not seem orange, to my brain, at that white balance.
try this
tonight, after sleeping for at least an hour, wake in full darkness and try the 5600k and the 3200k… which one seems more pleasant at that time, in that situation?
This may also be an example of people perceiving relative color intensities differently. For example, I have read blue sensitivity decreases with age, so people often develop a preference for cooler tints as they get older, in addition to some variation that I presume exists between people of the same age.
That might well be iamlucky13…. cause I am ’almost’ as old as dirt. 
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Two blue, both 3200k, en route for about £5 each.
Does anybody have an idea as to what kind of lifespan one might expect from the Yuji emitters? Is 20,000 hours a reasonable estimate, or do 5mm ones have shorter lifespans due to the lack of thermal path?
I figured, at two hours usage every single day for 27 years, this is $6.50 well spent! Looks like I may need to put my Sofirn C01’s into my will for my grandchildren……LOL…
I received my black one (5600k) yesterday, and loved it so much I ordered a blue and red one today. No problems getting the BLF discount updated (within 5-10 minutes both times).
The thermal path is poor, but the power level is very low. When I did overdrive testing, I remember the plastic dome felt warm after they spent several minutes above 150mA, but not hot. The C01 drives them at 25mA. Based on the forward voltage at this level (less than 2.9V), I don’t think the diode is being pushed any harder than typical.
I think 20,000 hours should be a reasonable ballpark. That should be 1000-2000 Eneloop cycles. It might take a couple years of non-stop runtime testing to determine if the LED fails before the Eneloop does.
I swapped a Yuji into a nightlight a year or two ago, but it’s a motion detecting kind, so it probably only has a couple hundred hours of runtime. Still working great, though.
I left a message for the seller for the BLF discount. Do I wait for further payment instructions? Or do I go back now and enter my credit card?
Wait until they change the price on your order. You will usually get an email about this, or you can just check your orders in your AliExpress Account to see if the price has been changed.
When it has, then you pay. 
Oh yeah, the price adjustment can happen in a few minutes or take as long as a day or two. But it will happen….
Wait for the price to change.
Got it. Thank you!