I second the suggestion for XS Big Dots. I wish I would have found this sight before I bought Trijicons for my XDm. My only problem with the Trijicons is that the front sight is a bit narrow for my liking. If you don't mind driving a bit, 21st Century Firearms in Bluffton (INGO supporter

) has Big Dots for Glocks and XDs for $125 and they will install them for free while you wait.