It depends on the look that interests you - I can see both names working and both have charm.
Peter and
Boyd are like two country brothers; sturdy, steady and cheery.
Peter and
Bernard are fine young gents who enjoy going out on the town, art, and wearing fancy boots.
I find
Bernard to be charmingly adorable myself, though I could never use it. Also
Pete and
Bernie is way cuter than
Pete and Boydie. :)