I own 6 TT 46 Pro's, a pair of TT42 GP's & a TT 61 Pro, (I also previously owned a TT 61 GP) -- all of them are superb pieces of work.

I think that the TT 46 Pro is arguably the best all-around 46-size sport engine on the planet. All six of my TT 46 Pro's have more than 100 hr of run-time on them & the highest time engine has 180 hr. They go like scalded cats & are as smooth as oiled silk.

I use only TT 46 Pro's on twins & seaplanes, where absolute reliability & never-die idle is required. Period

I used to buy OS engines by preference & I still have a few left, but I seldom buy an OS engine now.