If it's about the market price, than than yes i would transfer on the uPgrade of any 60's card to a BVG holder.
BVG has a Strong place in the market when it comes to Postwar and newer cards. For instance, i have an AROD Rookie Auto that was in another holder graded at a 10, crossed it to BVG 9.5/10(Auto). If you do some due diligence on this one you'll see what i mean. It's my Son's now
if it was Prewar, i would leave it in the SGC holder. Even if BVG were to uPgrade it numerically. SGC gaunantee's the card at the grade assigned for the lifetime of it! As long as it's not been tampered with.
imho, BVG is working very hard to gain ground in the Prewar arena, but still has some ways to go! Postwar seems to be stong in certain areas.