I would go with anything you mix yourself over Brownell's rattle can Gunkote. From my experience anything you mix and spray will be better than a rattle can. Rattle can's have the hardeners and solvent thinners mixed in, and use different stuff so it doesn't harden in the can. I have done a lot of painting with many different types of finishes, and self mix has always been more durable. I have also read many reviews stating the same. It may cost more and require more equipment, but you are applying this to a gun you probably paid hundreds for. Why trust it to a rattle can? And blasting can be done by any number of businesses, and won't cost much. Engine shops, machine shops, welding shops, auto body shops, most anywhere that deals with metal will have a blast cabinet and will probably blast your gun for $20 if you ask nice. I don't know where your located, but I will do it if you can't find someone.
Bottom line, you have a gun you probably value. Why put a sub-par finish on it? Spend the cash to do it right. If it chips and cracks you will regret it, and most likely will have to blast it again to get the finish back off. Unless ok is good enough, do it right or have someone do it for you.
Most places I see will coat a handgun for $120-170. Money well spent in my eyes.
From what I read, CeraKote is top of the line. It's ceramic based, and is tough as nails. Ceramic is one of the hardest materials, second to only diamond I believe. It's what I plan to use on my Remington 1100, as it will see a lot of salt in the duck blind.
Unless you have a spray gun and an oven, I would outsource. I would only trust my gun to someone with the right equipment and experience to ensure a quality finish that will last for years without issue.
This is only my opinion. Do as you wish. Just make sure whatever you choose will last, doing it twice won't save money in the end. Good luck.