I like all the ships, I don't really mind skulls, hidden cannons or red hulls etc. because they're toys, and I don't have any need for perfect historical accuracy here.
I'm still hoping to get the 4290, the only reason why I haven't bought it when it was released was lack of money and the need to make choices (like paying rent and getting decent food on the table). If I can still get it, I'll buy it before I'll buy the 5135.
re the red colours of the hull: I remember a discussion on Playmoboard about the shields of the vikings, people were complaining about the bright colours because those shields were made of wood. In fact the Danes and Norse painted their shields in bright colours for several reasons, so the perceived historical accuracy of the wood-coloured-shield-people was in fact mistaken. So my pirates paint their ships in bright colours too.
The only thing I never really liked was the big bertha, although it was the best weapon to actually knock over klickies with until the new bolt-shooting cannons. The older ones (especially those with the safety balls) simply weren't powerful enough.