Recs.
Updated
While not directly available for sale outside of Asia, you can still import the Mi 5. It has some of the best hardware currently available, at a selling price that converts to roughly $310USD.
Specs
Pros
Pro Superfast performance
The SoC (system on a chip) used is the Snapdragon 820 - one of the best available out there, and the same SoC in the new HTC 10, LG G5, and Galaxy S7 (the American model). To cut costs, they use the lowest bin number (each individual processor is tested and sorted according to its performance - high performing units are sent out to tier-1 manufacturers, while the slower chips are sent to Xiaomi). It still performs very well - in Geekbench it scores 4123 which is higher than some laptops available for purchase at the same price. The storage is also very fast - rated up to 450MB/s.
Pro Good battery life
The 3000mAh battery provides enough battery to last a full day, although it isn't exceptional. In real-world use, you can expect around 4h30m of screen on time, although this will differ greatly depending on how you use the phone. GSMArena rated the battery at 92h - a very good result.
Pro Lots of software updates
In China, Xiaomi will be pushing out weekly software updates. International models won't see quite as many updates, but still fairly frequent. Xiaomi sees themselves as a web-focused software company as opposed to a hardware company - their hardware serves primarily as a platform for their software, so these frequent software updates are certain to continue for the foreseeable future.
Cons
Con Heavily skinned software
Although this is personal preference and you can install a launcher to remedy it, out-of-the-box the Mi5 has a very heavily skinned UI. There is no app drawer, and the multi-tasking panel only show 3 apps at a time in a horizontally scrolling list. Icons look similar to an iPhone, and uses the same notification badge as well.