blue sig, i think. It looks better
i like the:
small writing and the bright white eyes
also the blue just makes it look better
and also the red one makes the location of the face look not as good... the blue face looks like it has depth

the face on the blue:
looks bettter skinnear
looks better smaller
looks more lively

mabe add a border to the sig? a dark blue border on the blue sig?
just giving some advice and my opinion XD