I flew both the F and the M model. Good airplanes, both, but the F had many more problems. I can't tell you how many times that thing tried to kill me. Most notably, and potentially more disastrous, was the time I landed in Sedona (KSEZ; high density altitude). I was about 50 feet from touchdown and the engine failed. I had the aircraft leaned for the elevation, so I was sure that wasn't it. As we exited the aircraft to push it onto a taxiway we saw avgas gushing out of the cowling. Apparently, a fuel line sheared at an AN fitting. Had this happened any earlier in the approach, I wouldn't be here to tell about it.
Watch the maintenance on the aircraft. The 225 series engines are not easy to maintain. This aircraft had the hydraulic prop, but still the prop would not attain proper settings. For every hour of flight, we spent about 2.5 hours in the shop. Fortunately, the owner had gobs of money that he could pour into the aircraft, but he finally sold it after $60,000 in maintenance. This was after $60,000 on refurbishment. I think he unloaded it for $80,000.
If your aircraft has the aux tanks installed, use them only in straight and level flight, just like the limitation says. Trust me.
Noise levels are unbelievable. We could not take the aircraft into Torrance (KTOA) because the prop created so much noise on takeoff.
Nonetheless, I had a blast flying it. It taught me not to trust airplanes for anything, and to second guess everything.