I just started playing last year 18 months after having spinal fusion surgery to fuse my L5/S1. Started with a set of Adams Idea A07 irons with hybrid 3/4 with graphite regular flex shafts. I spent all last year working on my swing because I couldn't hit the ball straight or draw. I was push slicing everything. This year I had another lesson after a year of doing my own work, made 2 adjustments (grip and releasing hips earlier) and I am striping the ball. I swing about 97 MPH with a driver and about 85 MPH with my irons just for some background. I was hitting my adams 5 iron (full cavity back) about 210 yards dead straight or with a fade.
I was tired of the fade and was playing enough (3 rds a week) and my swing was solid enough to try my dad's 17 year old "Mizuno T-Zoid Pro I" because I wanted more feel with my shots and thought that the add weight of the club would help hit down on the ball. Whether that was the case or not, I have played 5 rounds in the last couple weeks with them and am now hitting my 5 iron 220-230 yards with a slight draw. I have no idea if everything just clicked with these clubs but my good shots are now way better and with more control and I am hitting the clubs farther than newer technology. I went to the PGA superstore in denver yesterday to check my lie angle for the Mizunos, the fitter had me hit new ping's that were similar to my Mizuno's just this years model and I was still hitting the Mizuno's just as far and I still felt like I had more control. The guy literally told me to stick with the Mizuno's rather than try to sell me new ones.
Eventhough I still occasionally mishit (mostly hitting off toe) and lose distance but I don't slice anymore and my mishits are going straight.
It will probably be a while before I switch to different clubs because I just hit these so well, but like the previous posters indicated work on your swing first and make sure you are comfortable then move to these clubs because they are still hard to hit if your swing is not in tune. My suggestion as someone who just switched, I would use the cavity back clubs that are more forgiving for a round and then play a round with the Mizuno's, trust me you will know where your swing is at after that round. Your hands will hurt if you mishit these irons. But when you hit it right, it is like hot knife through butter.