I'm in the process of putting on Interlux Pre-Kote and Interlux Brightside. Waiting for a nice day! I've used marine
paint before this. It
can be finicky (depending on prep and weather mostly)! BUT if prepped according to instructions and applied according to instructions, you'll have a tough and shiny DIY paintjob with minimal tool-purchasing/experience.
All marine paints I've used can all be "rolled and tipped" or sprayed. I'm spraying primer (so theoretically I don't have as many ridges = less sanding) and "rolling and tipping" Brightside (because I don't trust myself spraying topcoat, and I've had exceptional results rolling and tipping). I can't really speak from experience for spraying marine paint because I have not done it (yet), but I know people who have with success. Most boatyards don't let people spray, so most marine paint is rolled/tipped and designed to be easily rolled/tipped without looking too ridgy.
For the record (I will share this because I had some difficulty finding out exactly what people did...), I am planning on spraying 2-3 coats of Interlux Pre-Kote, roll and tipping 2-3 coats of Brightside, and sanding in between all coats. I bought 1 gallon of Prekote, 4 qts of Brightside, some random Interlux thinners/gelcoat cleaner, 4" foam rollers, 3" foam brushes and my bill is around $260. Throw in sandpaper, rags, tack cloth and someother stuff and that's maybe another 20-30 bucks.
As far as other options...I've used the following on sailboats before with great gloss and adhesion.
Brightside is a one-part polyurethane - you only have to mix in thinner. Easiest to apply of probably all marine paints. Limited color choices. I've read you can mix different colors of Brightside, but I'm not daring enough! Less toxic than many marine paints - but still wear a respirator!
Interlux Perfection, which is a two-part polyurethane - more durable than Brightside and more color choices. Requires basic chemistry or bar tending skills.
AwlBright - Used by professionals in marine and aviation. This stuff is like liquid steel and looks beautiful. BUT it costs many pretty-pennies and is pretty toxic.
My guess, based on forum searching I did (I recommend you search the forum's too! Lots of good resources on people who have dared to go before us.) would be that the majority of people who used marine paint, used Interlux Brightside. I could be wrong. Brightside is $$ cheap-ish, good quality and pretty easy to DIY.
I will also throw out another option that I avoided - Rustoleum (Tremclad in Canada). It's probably cheaper than marine paint, and more readily available for those in landlocked states/provinces. I know people have used it on our trailers with success, but I opted for marine paint because I reasoned it gave me a slightly better chance of not having to re-do all the sanding and repainting in x-number of years. All the scraping of old paint and sanding is still TOO REAL!!!!
Do some research. Determine what your budget is. Compare. Agonize. Prep. Prep. Lay down the money. Paint and go camping! It'll turn out great! Best of luck.