What do you mean by nothing more?
Besides being very accurate, the 220 is light, reliable, and ammo is easily found. Quite possibly the best mass produced slug gun. I recall back when they first came out they were approx $450-500 and within a few years they jumped to $600-700 due to demand. I had a heck of a time finding one, but when I did I was glad to finally have one for the $500. Not sure what prices are like these days.
Some people scoff at the “little” 20 gauge slugs, but dead is dead.
As for the 350, unless ammo is significantly cheaper and/or the 350 is much more accurate with more range, I cannot see very many people selling their slug guns.