Having owned one long keeler - a Victory 40, and now a not so extreme fin and spade rudder Westerly Oceanlord, I would have these observations.
1. The Victory would stay straight as a die on reaches broad reaches and running, so if you were doing 8 knots, you covered 8 knots. The Oceanlord whilst being easy to helm down wind, has a tendency to sail a track that looks like a snake has been there. So 8 knots is not what you get. The Victory was the only boat I managed 200 miles in 24 hours. (she's a motor sailer)
2. Off wind sailing is harder for the helmsman with the Oceanlord, though not as impossible as a Bav38 holiday I sailed once. The Victory had no tendency to broach - at least I never had one even under spinnaker.
3. The Oceanlord is much nicer for living on, though holds less fuel 45Gals (200 gals) water 100 gal (200 gals)
What would I ideally like? A boat designed by Vandestatt with the cut away forefoot long keel and balanced rudder of the Victory and the accommodation of the oceanlord.