I've made extensive use of Quickdraw myself. My main Living Greyhawk character is a fighter/wizard who uses a variety of weapons. So, especially with a limited number of feats, weapon focus wasn't a particulary good choice for him.
So, if he's fighting a foe at reach, he'll use his reach weapon. If he's fighting a foe close-up, he'll drop the guisarm and quickdraw a different weapon and still make a full attack. At lower levels (before iterative attacks, when shields stacked with the Shield spell, and before his Shield spells lasted 11 minutes), he would often use a move action to ready his shield, quickdraw a weapon, and still attack. Without quickdraw, switching from a two handed weapon to a weapon and shield either takes two rounds (denying two full attacks) or one round of not attacking at all. With quickdraw, you can switch from the two-handed weapon to a weapon and shield and still attack.
Quickdraw is also useful for when he wants wands out or the ability to make full attacks with thrown weapons (not that that's really come up yet).