Bill,
I understand what you are saying - everyone I've spoken to who has or flies a 150/150 likes them, although, as a tailwheel airplanes, they do not handle as nicely on the ground as a 120/140.
The 180 HP conversion I flew regularly climbed beautifully, but was not particularly pleasant in cruising flight. It was not a well harmonized installation and always felt as if it was beating its way through the air rather than flying. The gear was far too soft, making landings challenging and directional control a pain in the whatsis - the other tow planes were Piper Pawnees, the 180/150 was the worst of the bunch on the ground. I figured, conservatively, on 10 GPH for fuel consumption, meaning fuel was a constant concern. (In cruise you had to pull the power back a great deal and could get the fuel burn back below 8 GPH, but that still meant brief endurance.)
It was not a fun airplane to fly - the combination of squirrely ground handling and less than good manners in cruise on the airplane I flew didn't make it my first choice of machines. As a working airplane, it was a very good glider tow - although we didn't put low time tailwheel pilots in it (we used it for checkouts quite a bit). For me, after towing in the 180 HP Scout and the 180/150, I'll take the Scout every time (although I prefer the flaps on the 150) because of handling in the air and on the ground and cabin comfort - as well as legal useful load.
Your mileage may vary, but from what I can tell, the 150/150 is a well-harmonized conversion - adding the extra 30 HP feels like the conversion was done with a meat axe rather than a scalpel and erased a number of the delightful handling qualities of the 150.
Warmest regards,
Rick
