Some free rental weekend testing results...
Currently, trying the Fusion driver (L85) and 3w (L86), the Steelhead irons (L85), and two (56 & 60 degree) Mack Daddys (L67, L68). My trusty RTX 64-deg (L80) and Nike putter (L89) round out the set.
Since I have the equivalent Nike clubs, I played several practice rounds (Legend setup, PB, PH2, RSG, StA) comparing the brands, head-to-head with the drivers and 3 woods, and alternate rounds with the irons. Using a Callaway L33 ball, both brands performed about the same: carry distance, roll, wind effect, and response to spin increase/decrease. Although it could be a placebo, I found the slower meter Callaways slightly easier to ding consistently.
Comparing the wedges was a different story: the difference in precision, forgiveness and spin is readily apparent. Rated distance is the same for the 56-deg MD and 56-deg RTX for all the shot types, and similarly for the 60 degree clubs. Full fairway shots required 33% backspin to get the MD to stop like the RTX (moderate wind conditions). Rollout wasn't predictable either. Overall I found the MD shots were at most 2-4 yds off from the RTX. With practice, I could probably learn to reduce that margin. Recovery from sand or rough seems to be similar. Was hoping the MD would conquer the 60/70 rough, but so far I haven't seen it.
Finally, I have begun playing rounds using all the trial clubs, with 64-deg RTX, Nike putter and Callaway L33 ball. So far, they're all ending up as expected: similar stats, and scores. I do find the MD's nicely meter matched to the rest of the set, and that makes the RTX meter seem pretty fast.
I have a feeling that when I go back to my L9x TM clubs (longer, higher flight, more accurate, but less-forgiving), I will spend a lot of time in unpleasant places until I re-learn how to manage the 3.0 meter.
Play well, --Berto