That's a great question. As it turns out, I spoke with a representative of GCW this afternoon & asked that very question. I was told that over time on the market, that production relating to that/those issues has improved with production runs, etc.
I presented the question since I, too, was concerned about this myself. I wanted to make sure that was the case & I was reassured that many of those kinds of issues are nonexistent now.
Now, personally, I have no idea... I recall only ordering one unit from Thinkgeek.com when they were selling prior to being acquired by Gamestop. From my experience of my unit that I purchased, it did NOT have any of those sticky button/dpad issues that I kept hearing about.
So, as of now, I wouldn't worry too much about that with a new production one that should happen soon that I plan on providing. If you would like more information about it, you can always email GCW at their address that is located over at www.gcw-zero.com
However, it's a great question that you bring up since I am hoping to become a steady reseller of the unit in the near future.