(from my site: http://www.members.cox.net/gregjwillis)

CLUBFACE TYPE
There are 2 basic types: Perimeter weighted cast iron, and forged blades. I have seen forged perimeter clubs, but not cast iron blades. What perimeter weighting gets you is a bigger hitting area by putting more weight on the outside part of the club face and take away that weight from the middle. Your missed shots are more solid and go farther because there's more weight in the missed area to hit the ball with. Forged blades are less forgiving for the missed shots, but the solid shots are better then the solid shots of a perimeter-weighted club. Better players tend play blades and beginners tend to play perimeter clubs. But that is all up to your preference and style. If you like to move the ball left to right and right to left a lot, it is harder to do the with perimeter clubs because they are designed to counter that action.