I have been playing around a bit with the Mizuno L90 3w. it seemed to me that the arch was noticeably higher than my med/high 250y Fusion. The meter on the Mizuno is 4.0 and the Fusion is 4.2. However, with the larger striking area, it seems to me that I can control the shot better with the Mizuno, although that may just be me due to the visual.
Last night I did a quick test of both clubs trying for the same thing to see if it verified what I thought I was seeing. This is not very scientific, as the sample is so small (5 shots total), but it did what I expected and what I thought I had been seeing.
First was 3 shots from the tee at Bethpage. One full shot with the Fusion on full backspin. Then one shot with the Fusion adjusting to the 242y rating of the Mizuno. Then one full shot with full backspin from the Mizuno. Once again, all shots were full backspin.
Fusion @ Full power: 269y carry / 0 roll / 129' Apex
Fusion @ 96% power 259y carry / 1y roll / 111' Apex
Mizuno @ Full power 262y carry / 1y roll / 117' Apex
Next I put the ball out in the fairway with 229y/230y to the pin. I played both clubs the best I could with full backspin. I had my usual miss (slightly early on both shots, but slightly better with the Mizuno). On both shots I got the distance exactly right (a small miracle), and both shots were as I expected in relation to how they were hit. On these shots you can see a much bigger difference in the arch and the roll.
Fusion @ 92% power 215y carry / 14y roll / 69' Apex
Mizuno @ 94% power 220y carry / 10y roll / 78' Apex
Both clubs play very well (other than I hate hitting a 3w for my lack of control with it). I think it is always better to be able to take as close to a full swing as possible for best performance. My conclusion is what I had expected. It is a little easier "for me" to control the Mizuno. The high loft carries better and lands better for shots that can be reached with it. At the same time, it is virtually useless for holes that take the 250y 3w to reach.
The Mizuno is a great club to have for some situations (those that can be reached with it), and I like having it, but I am not about to give up my Fusion on a course like Oakmont, Pinehurst, or Erin Hills.
I would be interested to know if anyone has compared the Mizuno to a 242y 3w with med/high loft.