Very few would know about the change and fewer would care.
Whichever is in better condition would be what i would want as a buyer.
Whichwver is cheaper would be what i would want as a seller.

You have a higer group crank in hand which means less money out of your pocket and gives the buyer round instead of biopace rings...id say you have what you should use right there.

I have a few bikes with biopace/ovaltech. They are fine by me, but as OJ said- they can be unappreciated by many.