It is the right size for anyone and is very enjoyable to use.
If your going to buy a xbox controller get this one.
Firstly, size. It's obviously great for anyone with smaller hands, but even those with bigger hands will like it - unlike the old controller, your hands don't ache after a couple of hours gaming, and the positioning of the joysticks just feels totally right. The ABXY buttons are actually better - they're circular, rather than elliptical, and have a smooth top rather than the ridge of the original, meaning more comfort. The build quality is actually better - the controller S has a solid feel, and sits perfectly in the hand.
The cable is also slightly thicker, adding to the quality feel of the product. One slight gripe - the black and white buttons sometimes feel a bit too embedded in the controller, but apart from that it's fantastic.
The Japanese market found themselves with another reason why an Xbox wasn't really an essential purchase since they couldn't get their mitts round them. Luckily Microsoft came up with Controller S version.
Its still the biggest of the controllers when you look at the official GameCube and PS2 controllers but its a hell of alot better than the original.
Where it suceeds over its competitors is the superior control that it offers for FPS games and the fact that you plug your Live headset in through it. The analogue joysticks are nice and firm to help get that greater degree of accuracy, however, I have noticed in particularly hectic moments in Halo that its a bit too easy to jam your hand on the black and white buttons by accident. Also I tended to end up with crampy hands after a while. Still not quite up with the PS2 controller as far as comfort goes.
One neat feature is the safety release device built into the cable... ensuring that if a rampant child happens to trip over the wire, it disconnects from the machine with ease rather than bringing all 7 tonnes of the Xbox down on its head.
A good controller that still needs to work out where to stick the black/white buttons. Essential to everyone who gets the machine, lose the clunky original controller immediately.