I bought the first gen one a few weeks ago. The scroll wheel failed within the first week (middle click still worked).

I just bought the second gen one, and it seems to be going alright so far.

As an aside regarding Anker, I left a review on the original mouse on Amazon saying how the scroll wheel wasn't working and got an email with a day from Anker confirming my address to send out a new one.

It hasn't arrived yet, but I was pleased with their customer service in that regard (I didn't expect it, hence ordering a new one!)