Created a live USB using universal USB Installer. (I've done this before with the two previous versions of tails, so I know how it works...)
For some reason version 0.14 just doesn't boot. Black screen, says 'Boot: _' but nothing happening. Any suggestions?

It looks like you got a boot prompt. Did you try pressing the Enter key?
What happens to me is I may get a black screen with simply the message:
in the upper left-hand side of the screen.
When I get a Boot error like this I hit Ctrl-Alt-F7 which usually gets a
prompt on the black screen to which I hit the Enter key.
Then Tails boots up for me.