I'm in research mode in building my AR10. The AR15 I have, I will give to my wife once the AR10 is complete. However, I will wind up building one and re-building the other in the end of it all. My question is about painting the weapons. The AR10 will wind up with a blue color scheme, and the AR15 will be a purple color scheme.

What are the best paint options available? (i.e. quality, durability, price, etc..)

What are the do's and don'ts in painting an AR platform?

Cerakote.

If durability is a concern, Cerakote is pretty much your only option.

Aevroe paint

Don't make your gun look like an Easter egg.

This really depends on you.  If durability is your goal, then they are rated:  spray can finishes, Alumahide, Duracoat, moly resin, KG Gunkote, and Cerakote.  With Cerakote being the best, and good ol' Rustoleum being the least durable.

If you look at the directions for any of the good brands they pretty much explain how to do it.  Some things to consider.  Prep is at least 50% of the deal.  The better you prepare the surface, the more durable your finish will be.  The best is sand or bead blasting.  The worst is just a chemical wipe.  In between you have scotch brite, chemical removal, etc.  

With a really good (thin) professional coating, I break everything down and spray inside and out, on things like uppers and lowers.  With spray cans and cheap spray guns you can't do this well because the paint is usually too thick.  

You can basically jump in on this thing at any level.  I've seen some pretty good finishes using just about any coating available.  A lot of it depends on you, your skill, and how much you want to invest.  

A simple gravity feed gun and small compressor will get you up and running for the better finishes.  A blast cab is very nice, but as long as you have a good machine shop near, you don't need it initially, although if you find you want to keep doing this, you'll want to get one.

For the baking finishes, the home oven will work, however you want to be very careful here.  Buy a shit-load of scented candles to cover the smell and you'll probably be OK.  

If you just decide to spray can it, the finish will wear off quickly, easily within one season.  The other finishes will wear, to varying degrees.  For instance Duracoat wear about 50% more than Cerokote.  KG Gunkote about 25% more.  So Duracoat will scratch up and probably need touch-up within a year, KG Gunkote the same, although not as much.  Cerokote will eventually scuff up a bit, but you really have to work at it.  I'd say most folks don't use their weapons enough to get there.

So herein lies the key.  If you actually use your weapons on a regular basis, then you want the most durable finish you can get.