Failure rate on Banggood's Arduino Nano circuit board

Recently I began to experiment with Arduino - In my earlier life, I worked with electronics quite a bit.

This post is to report my experience with the failure rate of a particular product from a particular vendor - do not over interpret.

The product I evaluated is:
http://www.banggood.com/5Pcs-ATmega328P-Arduino-Compatible-Nano-V3-Improved-Version-With-USB-p-951782.html

The failure rate is 16% - 4 out of 25 Arduino nano board are bad.

* This board needs driver from:
    http://wch.cn/downloads.php?name=pro&proid=5

Problems ranging from:
1.  Unknown Device - PC recognized a USB device being attached but do not
      know what kind.

2.  No Action:
      PC does not even a USB device is being attached.
3.  Not in sync. PC recognized the Nano and allocated COM5. But when try to
      upload a program, I receive the error message:
          avrdude: stk500_getsync(): not in sync: resp=0x00

I will see what Banggood.com would do and report back. For now, just plan ahead and take the fail rate into your order and expecting 16% of your order could be bad.

========= Update 20150411 ========
Just got the replacement from Banggood. I am happy with their customer service.