You can pick the Mi2 up on eBay. The phone is geared for the China market, so you're on your own for support and warranty.
I've used a Xiaomi in China. It was a decent phone, but the build quality felt a little cheap compared to LG and Apple. I'll stick with the Nexus 4 for now. It's cheaper and makes better engineering tradeoffs. Without a larger CCD surface area, the 13Mp camera means worse low light photos. Likewise the 1080p screen is indistinguishable from a 720, but gets worse FPS in games and drains the battery faster.
I've used a Xiaomi in China. It was a decent phone, but the build quality felt a little cheap compared to LG and Apple. I'll stick with the Nexus 4 for now. It's cheaper and makes better engineering tradeoffs. Without a larger CCD surface area, the 13Mp camera means worse low light photos. Likewise the 1080p screen is indistinguishable from a 720, but gets worse FPS in games and drains the battery faster.