My story:
When I started golfing in the early 90s, I played blades because the pros played blades, so if you want to be good you gotta play blades, right ?
I started working at a golf shop and got on a vintage forged blade kick (the ’60s Wilson Staff with Turfrider Sole were made from SOFT steel, they bent like butter). I knew I needed upright clubs, so bendability was important.

In the late ’90s I was at the range and someone let me try their 1995 Big Bertha irons – HOLY CRAP ! I was an instant convert. They were so much ridiculously easier to hit than blades. Our golf shop had good Big Bertha copies so I made myself a complete set 1-LW and bent them upright, I used those for 15 years.

Then I decided to buy a set of Ping G25s, because Ping makes it easy to buy upright (or flat) irons. The G25s were good, I was happy.

Then I discovered the MPF charts.

The 2010 groove rule had come out, and I wanted conforming irons to try USGA qualifying, and the highest post-2010 Ping mpf was the Ping Gmax(MPF 939), so I found an upright set, and yes, they are noticeably more forgiving and easier to hit than the G25s(MPF 821).
I also wanted to try maximum upright (Maroon dot 5* upright), and I found a Ping K15 (MPF 894) maroon dot set, because the MPF chart showed there shouldn’t be much difference compared to the G-Max set, and yes, the K15s are every bit as forgiving and easy to hit as the G-max.

Recently I wanted to try irons with maximum MOI, so I found a set of Ping G410s (MPF 738), but with essentially the highest MOI (19.04) from any manufacturer head ever.
Nope.
They were NOT as easy to hit or as forgiving as the G-Max or K15.

I’d always wanted to try the absolute max MPF irons ever (MPF 1200+), but it’s almost impossible to find a full/decent set.
But just recently I bought a mint set of Maltby Glider Xs 3-P (MPF 1209).
There’s so much to talk about these irons that I’m going to start a separate thread.
To be continued…