The Petzl Spirit Express Quickdraw is the Cadillac of all quickdraws. It's smooth cutting action is unmatched and I definitely notice a difference in the ease of string clips in it when I'm on the sharp end. This is the notchless keyhole design sets the standard for all muskets on the market, because they are much easier to clip and it makes a clipping them a smooth operation. Whether you're on the lead or cleaning them on the top rope, you'll do less fighting with the quickdraw putting them on and removing them all they're cut off at.
The Spirit Express Quickdraw is also equipped with a right-door musket and a folded-door musket. Remember the right door is always attached to the metal hanger on the bolt and the folded door makes it more ergonomic to cut the rope in it. The strap (aka dogbone) that connects the two muskets is nice and sturdy, making them more durable and easy to grasp if you ever feel the urge of free French through a section of a climb. The dog bone is nice and stiff which makes cutting out of reach bolts a touch easier.