Just a warning with the yubikeys. I had to use a solution that had these for a few months. The USB port of my laptop (2011 MBP) was pretty much worn out due the physical insertion and removal - other stuff would just fall out. Eventually this port blew entirely stopped working.
This is not specific to the MBP as a colleague's ThinkPad had the same problem.
This is not specific to the MBP as a colleague's ThinkPad had the same problem.