Aw, some of you make me sad. I’ve had two Irish setters from show lines and both have been very bright. I will say that they are very sensitive and would shut down if someone were impatient or sharp with them.
Irish setters are definitely not for everyone. Mine have been jokesters, a touch willful, and with grooming and exercise require a good deal of maintenance. They have vibrant temperaments and stay puppy-like for much longer than other breeds.
I also own a field English setter and he is an angel. A bit simple minded, but a wonderful dog all around. Deafness can be a problem with the breed, but mine has a “hood” (color in both ears and over the top of the head) and full hearing. His generous flews, however, do result in his tendency to drool, as can be the case with English and Gordons – worth mentioning in case you have an aversion to slobber.
I’ve known and cared for lots of setters – the English tend to be the most laid back but I’ve met some Llewellins that were anything but. 'Same for Gordons. So wbockman is right; do your homework, know your bloodlines and the potential health problems each breed can have. Before you pick a pup, try to meet parents and related siblings if at all possible.
Regardless of breed, remember too that if you are going to do conformation showing, you will have to keep your setter intact. That requires some special consideration in its own right.