My experience with powdercoat is as follows:
It holds up pretty well and is easy to apply. It is a bit more durable than paint -but it can chip and scratch.
It is not good at filling or flowing into seams. I have had car wheels powdercoated, and I have bought factory trailer wheels that are powdercoated - and the rust starts to show at the seam where the inner part joins the outer rim. When the powder is applied it covers the seam - but when heated and melted it does not flow into the seam. For this applicaiton I always take some matching paint and flow it into the seam after the powdercoating is done. (This should not be a problem on a Savage Tank - except for the mounting tabs.)
Powdercoating can fade if left in the sun. I have a mailbox that was powdercoated and the silver box is fine - the red flag is now pink after being in the sun for 5 years.....but there is not any rust.
Powdercoating is not an extremely shiny paint - it is more of a satin finish. It can be clearcoated with paint or clear powder and the shine becomes better.
It is resistant to fuel lifting the paint - but I am not sure about staining as I have never had anything powdercoated that is near fuel. I just ran by a local place that does a lot of powdercoating for cars. They said they have coated intake manifolds and they hold up well, and they have done a few of the small fuel tanks for race cars - but have not had any follow up. They think it wold hold up OK....but don't know about staining if the fuel was spilled on it frequently.
While I was at the powdercoaters I saw some of their fencing that shows the seam problem. The powdercoat is electrostatic and just like chrome plating - it is not pulled into seams very well.