Here's a P12 driver that had failed at the solder joints indicated by the arrows. Seems like repeated pressing of the side button caused micro fractures on the (lead-free) solder joints. This was a very simple fix though i highly recommend you don't press too hard on the button
Next is an EC25. Water came in through the side button. Turned the copper green especially on the other side of the PCB. Non-repairable
Next is an MH25 with very poor workmanship on the driver:
So yes Nitecore is the least-reliable among the major chinese brands
Thanks to Overclocker for posting those pictures. I was about to get a Nitecore P12 for kicks when I saw it and realized that flaw. Yes we can't expect top notch quality at an average price but structural/design flaws immediately predisposes it to many problems.
That being said I have 2 SRT3s and 1 SRT5 that are durable IMHO. I do not baby them, have dropped them time and again. There're scratches and dings but they still work. The SRT ring seems well built and we've probably played with the ring more than we need to and show no signs of failing.
I really love the SRT UI and the compactness of the SRT3 and SRT5. Although the SRT5 isn't driven to 900+ Lumens we do get that extended runtime especially on 3400mAh (Nitecore rates 1hr 45 mins on 2600mAh).
Seems like I'll be sticking to the SRT3 and SRT5 for a long time.
An interesting thing is the SRT3 and SRT5 heads are lego-able so I bought adapters from cpfmarketplace for AAA, AA, 16340 to fit a 18650 form factor, put the SRT3 head on SRT5's body and you have a light that can handle AAA (10440), AA (14500), CR123 (16340) and 18650. Sure it's only 550 lumens max but the versatility is pretty sweet.
Only weird thing is they always provide an extra tailcap boot even though it seems extremely difficult to impossible for the lay person to service it if need be.