If you use an oil base paint like the Rustoleum, make sure you've got good ventilation. Set up a fan blowing fresh air in. The fumes can build up quickly and can be dangerous.
I painted the topsides and deck of my Columbia last year with Rustoleum Topside, it went on and has held up well. Got it at Menards for $11.50 a quart. Can't see any real difference between it and Brightside at three times the price.
I did the interior with latex paint several years ago and it too has worked very well. Did the ugly fake wood bulkheads in off white to match the fiberglass and refinished the teak trim bright. Used two coats of Glidden Gripper primer and two coats premium exterior semi gloss latex. Looks great. Latex won't flow out as smooth as oil can, it will leave a textured finish. I was careful with the roller to leave that texture even throughout each panel and it came out looking like it was supposed to be that way, about the same as the original laminate texture. If you want a smooth shiny finish, you'll need to use oil based and the Rustoleum should work great for that.
