I might be missing something here; genuine question.
Why would anybody pay US$12 for your card reader and then wait at least three months to receive the device, when they can buy something nearly identical today and
get a free USB to MicroUSB adapter, all for US$5.60 including shipping?
Is it as simple as that yours is just slightly smaller? (You don't provide dimensions, but a US quarter is approximately one inch in diameter, so it looks like your dimensions are probably about 0.8 x 0.8 inch, versus their 1.5 x 0.8 inch).
Or are you expecting your reader to offer higher throughput and/or lower power consumption than theirs, as well? What can you say about sustained read / write rates, and power consumption?
I'm genuinely curious why I would buy this. If it's just a matter of size, the difference in size is little enough that it seems unimportant, especially given it's double the cost and probably triple the time spent waiting. If it's a matter of significantly greater speed or lower power consumption though, I could see it being worthwhile.
Head of an Android household: HTC One X+ International 64GB, HTC One X International 32GB, Google Nexus 10, two hopelessly unstable Asus Eee Pad Transformers (32GB and 16GB, each with keyboard docks; remember -- friends don't let friends buy Asus), Samsung Galaxy Ace, and a Fuhu Nabi 2.