Maintenance. The Mooney is a pain in the ass to work
on. Everything is cramped and difficult, because it's such
a compact, low-drag package. Reminds me of a Japanese
sport bike - had to recently pull all the goofy fairings and
the radiator on one, to change the spark plugs with a
special tool. If that seems reasonable to you, you're
going to like working on a Mooney.
Even if you buy a Mooney that has been perfectly maintained
with no regard to cost (top 1%), the cost of the annuals
might surprise you. A really cheap one is going to be
$10,000 if you just toss the keys at an AMO.
If you buy a "bargain" Mooney that needs some TLC, your
maintenance costs are going to be substantial, as you
get caught up, changing stuff and fixing stuff that's been
deferred by the previous owner, who knew he was going
to sell it soon, so why spend money on fixing it? If he
spends $30,000 on maintenance, it might increase the
value of the aircraft $5,000 (in your dreams). Not a
good use of his money, so no one ever does it.
If you can write multiple $10,000 checks a year to an
AMO with a smile on your face, an older retractable might
just be the airplane for you.
Me, I did all my own maintenance and got a buddy to
sign the books. Parts cost alone will make your eyes
water, my time on the weekends and evenings was free.
I think I still have the landing gear tool in my toolbox.
[img width=500 height=255]
http://www.lasar.com/img/mods/mod-33-35_lg.jpg[/img]
Free advice: be choosey, and find an AME that's worked on
Mooneys before (that doesn't run screaming when you walk
up to him).
Don't just let a Cessna AME learn on your airplane. Likely
he will be a thief but as long as he knows Mooneys, he won't
hurt your airplane, only your wallet.