I picked up a lot of the Imperial Human ships because of the historical theme and the idea of using them in more historical games at some point. The basic premise of all the sailing factions is speed. Those ironclad dwarven steamships ignore wind direction, but they are too slow for my taste. I've been playing elves most of the time, some of the fastest ships in all of the Uncharted Seas.
The human faction also has a faith/religious element--I've been thinking of trying to paint mine in a yellow and red theme along the lines of the Spanish Armada because they have spells which feature a Catholic sort of flavor to heal wounded crew and stricken enemy ships with mysterious ill-fortune. They also have those infamous martyr ships which sail in close among enemy ships and then... blow themselves up! The new models are quite beautiful and received some well-deserved upgrades. I'm painting a pair of frigates for the online painting competition and the new frigate looks like a Spanish galleon while the old frigate looks more like a sailing raft.
I haven't seen the sky pirates ships out yet, but why not? Just stay away from the dwarves. Slow, heavily armed and armored, sure, but so damn slow. The battleship has 4" of movement and the frigates have 8" and once I got the models I just never felt inspired to paint them and gave them all away. Compared to the other factions, the dwarven ironclads just look like... well, uninspired and boring Civil War ironclads. You know, a lot of Civil War era federal ironclads were painted black? Boring colors for fantasy ships. But the bellows sky blimp looks cool, and you could use that with your sky pirates...
I must admit I still don't own the new hardback copy. There was a copy at the game store where we ran the demo games yesterday, and I paged through it and almost bought it, but I told myself I should order it through the GV and support my own FLGS (especially since that other place really didn't help to promote the demo games day and the store manager and staff couldn't seem to care less that we were there trying to drum up interest among new players for some alternative miniatures games).
