Good points about the ability to make an instant choke selection with a DT gun. I don't think it's of much value for birds like grouse and woodcock, but with open country birds, it can come in very handy. I don't know how often I've done it on pheasants, but plenty of times for sure. On one pheasant hunt, I went straight to the rear trigger on 3 birds in a row. Worked fine on the first 2; missed #3.
Re cylinder patterns: Like anything else, density is a function of shot charge and shot size as well as choke. With something like 7/8 oz 8's, you're only going to put about 250 pellets in the 30" circle at 25 yards, and they'll likely be pretty well distributed. 1 1/4 oz 6's, pretty standard pheasant load, you're probably looking at something under 200 in the circle. But if you were to shoot a 12ga 1 1/8 oz target load of 8's (or worse yet, 8 1/2's or 9's--and I'll use both of those on woodcock, but in lighter loads)--you could well put more pellets in a grouse than you'd like. So you do need to look at the load you're shooting, because depending on your choice, cylinder can still give more density than you want at 25 yards.
