The guys have made good points so far.
A lot of folks are afraid to buy products from any place outside of the US, especially on eBay. It doesn't matter where the product is made, but buying direct from a non-US seller makes people nervous.
As far as design, I'm going to be very honest here. Please don't be offended. This is my opinion, and doesn't mean that you aren't building a good product.
Here is the Guru...
The interface is simple and looks very easy to use. It looks like a professionally made product.
Here is the Wolf...
The interface is confusing with a lot of buttons, LEDs, etc. Some things aren't labeled intuitively. It looks like someone bought a project box at Radio Shack and some rub-on lettering and built it in their basement.
Going beyond that, as Lionel mentioned, the folks at BBQ Guru are very active in BBQ here in the US. They are at competitions and they are winning. Other BBQers know who they are, and that helps a lot.