Powder coating involves baking the parts at high temperatures also. Sometimes we would get gun bodies back that were slightly out of shape. In an application where .001" is cruicial to keeping air in a chamber, this presented a problem for us.

I'd say a good 99% of people chose to anodize their bodies instead of powdercoating. The results were better, and mroe durable. The majority of the anodizing process, (if you care to get a shiny, lusterous surface) goes into the preparation, sanding and polishing, rather than the actually anodizing process. Also keep in mind that anodizing DOES remove a fraction of an thousands of an inch of material.