I hunt almost exclusively with 16ga guns. I have not found that 16ga ammo is "hard to come by". You may not find it in a rural store but WalMart, Dick's, Sportsman's, Cabela's, etc all carry 16ga ammo. You may not find as many ammo options as 12ga or 20ga but you will find good shells to suit your game.
I reload most of my ammo since I enjoy doing it along with saving some money. I also like loading paper hulls for my vintage guns. I don't think 16ga is "better" than any other but I do enjoy the 16ga guns I have.

What is your new acquisition?

With a fine gun on his arm, a man becomes a sporting gentleman, both on the field and off.