I just bought the TM Level 90 irons. They have a bit of a learning curve to them. But I immediately liked the yardages better than my Level 85 Nikes. As I'm learning the new clubs, overall, I find that I like them more than the Nikes.
They definitely have more stopping power, which has allowed me to get closer to some pins that I wasn't able to get very close to before. But the difference in scoring has not been dramatic. Even so, I haven't owned them that long and am still learning them. And I'm still learning which ball works best with them for me.
For the Nikes, the Callaway Chrome Soft Ball (L33+) was a great match for me. But I had a bit more difficulty with the TaylorMade RSi2 irons. So now I'm trying the Nike 20XI-X Ball (L71+), which is a more expensive ball.
Overall, I'm glad I bought them. But I had a bunch of extra credits, so if they hadn't worked out, I wasn't really out anything. YMMV
Bottom line: I think they're great clubs, but I don't think they're going to transform my game.