I have one with around 600 hours.
You will see the known typical benefits over fixed pitch such as better thrust in takeoff, ability to reduce rpm in cruise, noticeable braking effect if/when you want it, etc.
The MT I have is the 3 blade which as you may expect is very smooth; noticeably smoother than a 2 blade though I can't say it was much better than the 3 blade Catto I ran.
The MT I have is a little slower in cruise than the Catto I had, maybe 7-10 kts slower.
The MT has paint over the nickel leading edge which erodes with rain and personally I find it unsightly. The nickel leading edge has been excellent however for durability.
My MT is an older prop I bought with zero hours from a builder who bought it new but never installed it. As such I only paid a couple thousand for it. I have had to replace the P-120-u control unit at around $2,000 and the servo motor at around $1,000. I had it overhauled at MT Deland and within a few months of overhaul the prop suffered paint peeling off in sheets. I ended up having to have the prop stripped and repainted in under 6 months from overhaul.
Prior to replacing the control unit and servo it had a few occasions where I could not adjust the prop pitch in flight - it just remained in the pitch at time of failure.
The electric pitch change is slower than a hydraulic prop.
RV-9A (2013 - 2016)