And now for the follow up.
Cavity backs offer the least distance lost on off-center hits. This is also known as maximum forgiveness. Everybody should play them. And I do mean everybody.
Muscle-cavity
clubs are 2nd in the realm of forgiveness. The reason to play them is if you strike the ball better than average. You'll get a little more distance, as there is more weight behind the sweet spot. The tradeoff is when you do mis-hit, you'll lose more distance than with a cavity back. Still, more forgiving than either blades or musclebacks.
Blades have been known as 'players'
clubs for the longest time. I'm not sure why, but I'll assume it has something to do with the stigma of 'game improvement
clubs' when cavity back and muscle-cav
irons first came out. The guys on Tour wouldn't be caught dead with them. Only marginally more forgiving than muscle backs.
Musclebacks are the ultimate thing to hit when you nut them. Sweet feeling, long, any positive adjective will do. But if you mishit them, you know it, RIGHT AWAY. IMO, Muscleback
clubs are an ego thing. If they were really the bees knees, everyone on Tour would play them (having been around for a while). Instead, we've got guys on Tour playing cavity back
irons, and hybrid
clubs.