"IF" a 28 gauge or .410 Bore weighs as much as a 20 gauge I see only disadvantages to the smaller bore, no advantages what-so-ever. If one shoots only factory loads the 20 is certainly more economical & if one reloads the 20 can be loaded down & the gun is far more versatile. Maybe economy or versatility doesn't mean much to a lot of folks, but I'm a Pore Boy.

Miller/TN
I Didn't Say Everything I Said, Yogi Berra