The .410 is my "fun" gun. I have used it in the dove fields and use it regularly on skeet and sporting targets. Ammunition is MUCH more expensive for the .410 than for a 20 gauge. You give up at least 15 yards to a 20 gauge in practical range when hunting. Reloading for a .410 is a pain in the rear. The little shells don't last as long, and they are finicky about putting together good loads.
The 20 is a viable hunting gun. Shells cost the same as a 12 gauge, which is to say that they are among the least expensive. Recoil is about the same as a 12 gauge because the gun is proportionately lighter. In fact, a light 20 is a worse kicker than a standard 12. A lot of people who have not shot much 20 gauge think that, because the shell is smaller, the gun will kick less, but that just is not reality. Recoil with the .410 is a good deal less noticeable than with a 20. The shot load is about 1/2 to 2/3 that of the 20, and gun weight is typically only 10-20% lower. .410 shells are not nearly as widely available as 20's, nor are they available in nearly as many loads.
If you can only have one gun, get a 20. If you can have multiple guns, a .410 is great fun to own, carry, and use. Just use it within its limitations. I have, at last count, only one .410. It is a Wingmaster. I have five 20 gauge guns in pumps and autos. I don't yet have a 28, but when the right side by side comes along, it will be mine. The 28 gauge shells cost about the same as the .410's, by the way, and their availability is somewhat limited, so there is a downside to the 28.
Clemson