Fantastic. The steel shaft is almost as light as the graphite shaft. The forged construction is top-notch.
The distance, feel and control are truly outstanding. I will never go back to cast irons again. These forged clubs are at least 1 1/2 clubs longer than my Pings, have a superior feel, and are more forgiving even on mishits. The immediate feedback from hitting the sweet spot is almost addicting. As an intermediate player (high 80's)looking to improve, I wanted irons that I could "grow" into as I improved my game, but forgiving enough that it would not stymie my development. These irons fit the bill perfectly. Shape shots? No problem. Need effortless distance? You got it. Want to know when you've hit the sweet spot and when you've mishit? Gives immediate feedback.
The only complaint I have is the pitching wedge is lighter than I'm accustomed to. I prefer a heavier wedge.
Bottom line: Demo them. Borrow them. Buy them. Whatever. Just try them and you'll understand why so many have become Mizuno MX-20 addicts.