By adjusting the size of the panes (dragging the borders), I can get a bigger board from the new/premium version actually.
But in general if you aren't using the premium features, I guess it's mostly a question of aesthetics. :) The old one does look more like the rest of the site, so points for consistency..?
Is it just me, or is the old basic live chess better than the new live chess?
The old one looks better,(bigger board)