I have played Tensei Red in my irons but we went through a proper fitting so my "thoughts" would be, the only thing that matters is what feels right for your swing and gets you the result you need. Even if hundreds of people did not like Tensei Blue iron shafts, if they work for one individual, he/she should go with that shaft. I have never really understood the logic in asking for an open opinion to back up a personalized decision. Anyway, hope you either get a proper fitting or find a shaft that best matches your needs.

I have the Tensei (AV) blue in my T300s. Was fit at the Titleist fitting center at Pinehurst two years ago. These shafts performed better (for me) than the Red (AV) and the AMT Red Steel shaft. At my age (70) these shafts perform well for me and are much easier on the body. Using the Prov1x with these clubs I get the performance I am looking for. If it doesn't feel right, try another shaft. Your fitter will find the right shaft for you.

I have the Tensei (AV) blue in my T300s. Was fit at the Titleist fitting center at Pinehurst two years ago. These shafts performed better (for me) than the Red (AV) and the AMT Red Steel shaft. At my age (70) these shafts perform well for me and are much easier on the body. Using the Prov1x with these clubs I get the performance I am looking for. If it doesn't feel right, try another shaft. Your fitter will find the right shaft for you.

Can you explain why the AV Blue AM2 shafts performed better than the AV Red AM2 and AMT Red? Driver swing speed, tempo, etc.

Red have a lower flex point therefore would “kick” your club head more than the Blue, resulting is a higher overall ball flight. That lower kick point could also lead to less control of side spin.

I appreciate your comment Dale. I know the best thing would be a proper fitting, but that is not currently an option. I'm currently playing T300 (2021) irons 4-PW with AMT Red shafts in regular flex. Without knowing my swing etc., in your opinion would the Tensei Red or Blue be more appropriate for someone with a low 90s driver swing speed and a smooth transition/tempo.

Your speed is not as important an issue between Red or Blue as is your flight and accuracy. Red will launch higher but will also tend to flex closer to the head therefore exaggerate the dispersion. Swing speed should tell you more if you need a stiff, regular, or senior flex. Take all those things into consideration and pick which one you think will fit you the best. Good luck and hope it works out for you.

Also being from WI, there are multiple fitters in your area. We are past the season for the Titleist sponsored fitters, but Mike T in Janesville (used him while was at Beloit) has a full studio for clubs and TPI evaluations. I’m using Jeff at Nevada Bob’s in Madison because he is both a premier fitter and 3 miles from my house. I used the fitters at TPC Wisconsin when it was still Cherokee.
If you are looking to spend a fair sum for shafts even a $75 fitting fee is reasonable insurance. Swing speed is not a sole determinant. Your release and tempo will determine which shaft will generate the appropriate launch as well.
The AV Red and the TT AMT vary in no small part due to the graphite shaft being lighter. My irons T200 (2023) with the AV Red give me a better flight. I have a T350 (2021) with the AMT Red. It really only can be used for low punch shots from forested areas. The AV Blue will be too different from the AMT Red steel to say how it would perform for you.
As Dale alludes, our opinions are free and worth every penny to help you. …Get fit…