Not to take anything away form your decision but could you explain? That because of the part Tories played achieving Brexit? Or because you hope the Lib Dems will stop Brexit? Or both.
I am bias as I am a Brexiteer, however, knowing that Brexit is 100% going ahead, wouldn't you want the strongest party negotiating the best possible terms? I can't see the Lib Dems having the power, nor respect to get a half decent deal from the EU.
Best is largely subjective, dependent on your views on the single market and freedom of movement.