I'm using the Supermarine paints- So far, I've got the primer done on the whole boat, and SHOULD be painting the deck/topside this week, if I get my thinner!
I've experimented with their topside paint a bit, and so far I like it. I'm using a red, and I have had some coverage issues, but that's normal with a deeper color like that. I've switched to a deep colored primer, and hopefully that'll help me get more even coverage with the paint.
I went with these paints because I liked their gloss and durability, but they are still a one part paint that's a little easier to work with. I've used all different types of paint on boats- Everything from deck & porch paint to awlgrip, and just about everything in between. I wanted to find a paint that would have a high gloss, last a long time, but wasn't overly difficult to apply given the equipment I have on hand.
There are a LOT of different ways to go with paint, but you've got to balance out the pros and cons of each system, and find the paint that suits your needs the best. Plain old Rust-O-Leum does wonders, and is cheap. single part Polys are easy to apply, and offer great gloss, but cost a lot more and, at least in my experience, are a bit softer and require reapplication more frequently to keep up the shine. You can get in to a multipart paint, too- Which usually is going to last longer and be more glossy, but requires more attention and equipment to apply properly.
Just remember, whatever paint you choose, the key is the prep work... If the surface isn't perfect, you can use the most expensive, best paint in the world, and it's still going to look terrible. Some paint 'systems' require a certain type of primer be applied, that is compatible with the topcoats. Keep that in mind before choosing a primer!
-Andrew