I think the profile of the nRF51 is about to take a big leap forward, as the previous closed hardware design for the BBC Micro-bit, which has been rolled out around a million school children in the UK, has not been released on GitHub https://github.com/microbit-foundation/microbit-reference-design
There is a press release http://www.bbc.com/news/technology-37682405 indicating that the micro bit foundation will be encouraging the use of the design throughout the world.
I am not a lawyer, but the license appears to allow anyone to use these designs.
So if this is correct, I imagine that a lot of Chinese manufacturers would be interested in producing versions of this, because at the moment, they are only available in the UK and the cost is fairly high (£13)
Which would be good news if the price was brought down in line with boards like the Arduino Uno, or my favourite STM32 boards.