Try playing a game with ONLY cruisers and destroyers. A great change up, and every ship can harm anything on the table. There are plenty of historical battles without the big boys on hand.
I have both. Plenty of original ships for sisters, but I also have bought a lot of Shapeways as the minis tend to be better quality and look better when painted up.
I am working on basing all my major nation units on Reachers bases. Major units get sisters, and subs/DD/air/MTB get 4 of each class. Taking up 9 tackle boxes and a dozen Plano trays thus far. Easily have a couple hundred Shapeways planes alone.