Rimfire vs. Center Fire

What are the basic differences and would one be preferred over the other? 

Has any one had a pistol coated with Duracoat? I have a Smith & Wesson CS45 that tends to develop rust spots when I carry it in humid conditions, and in Florida that is most of the time. I believe the price is around $200.00. and it should not rust any more. Please let me know thoughts, comments, feedback etc.

Yes, I know there are other post that people have here about them, but I was hoping to get some new information now that people have had those radios for a time. How are they still functioning, or are they still working properly? Did they develop any problems? What about the new models that might have came out? The ones that are solar powered with a hand crank and can also charge your cell phone? If you were to recommend one brand name what would it be?