I've been flying the stock nose gear spring now since the beginning, both on grass and pavement, with no issues. Break out force is straight back, and your right to think it compresses easy and doesn't always extend that quickly while taxing, but the Vamp rotates on takeoff so easily I really haven't found the soft spring as an issue. The good thing about soft nose gear springs, they won't launch the plane back up following a not so perfect touchdown.
Jim