I recently got the Jem'Hadar set and was surprised that using all 3 pieces together gave my fleet escort a mandatory makeover - while I like the purple, I had chosen shiny metal and several other paint schemes before I equipped the set, and kinda liked what I had picked out.
I know the Assimilated and Aegis sets both give your ship a costume change, but the wiki isn't very clear about any of the others. What sets will allow me to spend a ridiculous amount of energy credits on a paint job and actually get to see it?
Ooo, and do the Assimilated and Aegis sets just sit on top of what you've picked out, or do they also change your metal type and ship paint job?
As a rule of thumb, the shield piece is usually the one that changes the appearance of the hull. The deflector piece adds a visual effect to the deflector (although the color change of the dish is linked to the shield) and the engine piece usually changes the visual effect of the engine trails (again, the shield changes the color of the engines themselves) the main exception to this is the borg set, which adds pieces of assimilated borg tech to the appropriate parts of the model, as well as changing the visual effect.
I haven't experimented much with non-standard paint schemes, but I'm pretty sure the Aegis and Borg sets (and the Breen set that has no hull visuals at all) are the only ones who's visuals do not override the existing hull paint scheme completely, and instead supplement it with their effect.