I have one from the US for an N5. Overall it's really good, but don't underestimate how big the thing makes the phone.
My N5 has turned into a phone that can only fit into a back pocket or a bag.
Great build quality. Comes with an Otterbox-style screen protector. Downsides besides gigantic size are:
1. Occasionally seems to mess up charging. i.e. last night the external battery charged up but the phone battery didn't charge at all.
2. If both batteries go flat, I've had to disassemble the case to charge the N5 first, before charging up the case battery.
3. You lose the ability to transfer data over USB cable (i.e. you have to use a wireless transfer method to hook it up to a computer).
4. If you end up ordering from Amazon, it's really easy to accidentally order just the case with not battery.