Yeah there are lots of examples where the DUO adds a lot of flexibility and much faster mode changing.
Take the basic Gears of War 2 preset for instance. The left tac button turns perfect active reload on and off. The right tac button turns rapid fire on and off. Then holding down the right tac will switch between modes 1-4. Modes 1-4 select which gun you want perfect active reload to work for. Rapidfire works for all weapons and can be turned on/off regardless of which mode you are in. In sleeper, you have to scroll all the way through modes 1, 2, 3 and 4 to mode '0' to turn rapidfire and perfect active reload off.
For COD5, for the Fast Reload glitch, the left tac turns the reload glitch on/off while the right tac turns rapidfire on/off. In sleeper, you have to scroll through modes 1, 2, 3, 4 to get back to mode '0' to turn both the reload glitch and the rapidfire off. Of course there are other COD5 presets for sleeper, such as presets that don't include the fast reload or sniper mode, if you don't want them at all.
etc....