I'm 6'4" but 220lb. I usually fly my F model with my wife so I guess I
don't notice it as much. I do know that its the same size as an Arrow
(I measured them side by side after many rumors that the Arrow was
bigger). In the Mooney world, the cabin doesn't get any bigger until
you jump into the M models (Bravo, Ovation, Eagle). The F, J, K all
have the same cabins. An M can cost you 1/4 million though.
I used to fly a Bonanza. If you compare year to year a Bonanza to a
Mooney the Mooney will run slightly faster but the Bonanza will burn
about 20% more fuel doing it. (Don't be tricked by B drivers who try to
compare a 1960 C Mooney with a 2005 F33 Bonanza ). As you said, you
have to pay for the extra room in terms of fuel.

The only real gottcha with the Mooney is that you have to be tall. My
partner is 5'10" and I would consider that minimum height for a Mooney.
He has to move the seat all the way to the front and can just reach the
rudders. In the Bonanza B33 I used to have my knees would rub against
the panel (I'm 6'4"). I do miss the "screw" throttle in the B though.

-Robert, M20F