Re: which paint?
You've asked a question that has many answers. Several folks swear the Rustoleum is a great product, (I think most of them are referring to the Marine grade).
Interluxes has a growing reputation as a top quality finish that can be applied by the common person without a lot of special equipment.
So the question that remains is durability and ease of applicaton. This is a tough one to answer but I'll try to rap it in a nutshell for you.
If you intend to store your boat on a trailer with bunks or you leave your boat in the water for over 72 hours then the paint you choose for the bottom of your boat, up to the normal waterline should be formulated for those conditions. Interlux's VC Performance is what I chose.
If you need a super hard bump and scrape resitant finish that can be easily cleaned repeatedly but is not submerged for long periods of time then you need a product formulated for that. I chose Interlux Perfection.
For most topside applications that are subject to human abuse (read as upredicatble loose cannon buddies and kids) you should choose a product that is easy to acquire, easy to apply and most importantly, easy to store. I chose Interlux Brightside.
The bad part about Interlux products (Brightside is the most lienient) is that they must be applied under strict conditions. The manufacturer is very good about providing documentation and even video's of the processes.
Finally, it's a question of if you're time and money budgets allow you to use Interlux correctly. If not, you're better value would definitly be in a great product like Rustoleum. My order of Interlux products for a 1991, 18' Starcraft painted to match the 2009 Model year, (you can see it on their website), cost me slightly over 700.00.
Hope that helps and doesn't make the matter more confusing for you.