Most of those "Euros" you speak about are guards or perimeter-oriented forwards that have to adjust to the NBA three-point line and defenses. That's not to say Scola wouldn't have to adjust to the more athletic post defenders, but I think since he relies on a game closer to the basket he'll have less of an adjustment period.
On his trade value, I've always maintained that the Spurs would be best served bringing him over and letting his game establish his trade value, rather than being an unknown commodity without a contract. But, if his "ship has sailed" it'll be interesting to see what the Spurs get for him.