Westerdam VF guarantee or VA guarantee

[JPSnipper]

:) My wife and I went on our first cruise April 2006 (Mexican Riviera, Oosterdam). The trip was a gift from family and had no choice of the cabin. We had VF4034 – which we thought was great. We are looking at sailing on the Westerdam this spring and I am thinking of either doing a VF Guarantee or VA Guarantee. I am hoping for at least a small upgrade. How realistic is it to move from V to S on a Vista class ship? Should I save a little and go with the VF? If S cabins are not sold out, do they fill those with VA Guarantee’s? I would appreciate any feedback. :)