M542's - £25 Chinese or £45 Leadshines?

[birchy]

As per title. I've read that the branded (i.e. Leadshine, etc) drives are superior to the unbranded ones...but is the 80% price increase justified? I'm a firm believer in "you get what you pay for" but am also aware that you can often pay a premium price for an identical item because it has a brand name on it.

I'm just wondering...what are the main differences between these various boards? I've recently bought a spare Chinese M542 driver off eBay and while peering through the air vents, I noticed that the component layout is different to the PM542 boards I bought form Zapp about 18 months ago. There seem to be several variations of these "M542" boards, including various names and numbers, but all having identical specifications. Are there any of these that should be strictly avoided or are they pretty much all the same in both quality and reliability? Are there any visual clues to tell us which style board is used, or is it just a case of suck it and see?

And while on the subject, assuming that the drive is fitted to a proven machine, what is the average lifespan? Under what circumstances do they fail? I've made some adaptors to provide forced cooling via 80mm fans mounted on each drive heatsink, but is that just overkill or a worthwhile upgrade?

Just for the record, judging by the 2 horizontal caps near the L.H. edge of the PCB, the unit I received from eBay seller "Sinedy" (a.k.a. "Buy In coins") appears to be the same style as this: