Tom's last point is the most important, in my opinion. When you have an extensive collection, as many of us do -- it takes a pretty spectacular Iris to make us sit up and take notice. But it's really no different for people who are just beginning their collection -- there are going to be Irises that *speak* to you, -- that make you stop and think "oh mannnnnnnnnnnn -- I have GOT to have that Iris". Personal taste. Fill your garden with flowers that make your heart happy.