Build Quality:
I have both the metal and the plastic Pistons. I use the plastic ones more as the headset controller is a little easier for me. I often sleep with them in. I have snagged the cable so many times I could not honestly make a warranty claim if they stopped working. But they don't stop working
The construction and materials even of these $12 items seems perfectly good: not fancy or elaborate or pretty but very well suited to the budget IEM life of being used a normal item that lives unregarded and uncared for in pockets, bags etc. The metal ones seem equally fine though I haven't used them nearly so much.
By comparison last year I bought a very nice sounding Samsung Headset (HS3303). It failed, I got a warranty replacement and also bought two spare pairs as they were a good price. One of the spares was faulty from new. I got a replacement. It failed....etc etc, long story but in the end I've had seven(!) pairs of these Samsungs pass through my hands, one turned out to be a fake (fulfilled by amazon) and three failed. They sound fabulous but I'm never buying another.
I had two pairs of RHA fail within a few weeks (one new, one warranty replacement).
I'm not a total psycho IEM destroyer - I have some very well used Sennheiser CX95 I bought in 2009 and they still work great (but no headset control so a bit less useful these days).
The Pistons were so cheap that I actually bought an extra pair of each, asuming they will probably break and this has to be cheaper than shipping them back to China if they break. But they don't break, so I have one each of gold Pistons and plastic Pistons, still boxed and new, just gathering dust.
btw vsonics breaking is no surprise. One of the best thing about amazon reviews of IEMs is when there are many tens or even hundreds of reviews you can easily learn what to avoid. Check out some popular Hifiman, Vsonic or RHA and note that the very high numbers of 3, 2 and 1 star reviews are almost all complaints about product failure and not fit, comfort, sound etc.