I whacked a squirrel the other day at better than 35 yards the other day with my smoothbore. I have also cut palying cards in half, split balls on an axe, hit popsicle sticks at 25 yards, cut strings, and hit a turkey sized target at 80 yards, and embarassed a couple of rifle shooters with my 20 gauge.
A smoothbore is like any other gun, it needs to be sighted in and it will do what you ask of it. There are a lot of advantages to smoothies, and while you won't necessarily become a precision shooter, you can still group nicely at 50, 75, even 100 yards when you get to know your gun.
All shooting is a relationship, and smoothbores are very much like women...you had better get to know what they like and treat them like your life depends on them!
One problem that first time smoothbore shooters run into is that they treat the smoothbore like a rifle and sight straight down the top of the barrel, and then find that it shoots low. Look at your rifle a minute, and more specifically look at the sights. They are raised above the plane of the barrel, aren't they? So when you hunker down on your sights, you are actually looking OVER the barrel. Don't drop your head so far on a smoothie. More importantly, put it on the bench and sight it in just like you would a rifle before you go bending ANYTHING! Plan to spend the day.
Smoothbores are very user friendly, and I thoroughly enjoy shooting mine, and I am building my 3rd as we speak...well, not as we speak...as we speak I am typing this in my office and ducking work for a few minutes, but you get the idea.
Anyway, hope all of that runaround helps. Prepare for the flood of responses to your question...glad I got here first!