I use IK all the time. Vicky can't dance without it. Can't do a chin up on a bar. Can't do a pushup. Well, she CAN do all those things without IK, but her hands and feet just don't stay where they should without IK. So if you do animation and you want a fit Vicky, you'd better keep IK.

That said, I edited all my CR2s so IK is off when they load. But I have a variety of pose files which turn IK on or off for various IK chains. (As I recall, I have lesbentley to thank for those!) The pose files make it quick and easy to change IK settings.