As hokey as it sounds, my first criteria is the condition of the shop
floor.
The shop which does my work has two hangars both with pristine white
floors.
The shops I didn't choose have dirty unpainted floors. I believe there's
a
correlation between clean/neat facilities and competent work, but maybe
I'm
just fooling myself.

I felt the same way, but soon found that the "clean white floors" were also
considerably more expensive. They were the corporate shop, that "punched
in" on your plane at 8 AM, and "punched out" at 5 PM -- regardless of
progress or results.

My current mechanic is a long-term EAA and AAA (Antique Aircraft
Association) member who works a full-time job (a chief mechanic for Airborne
Express) as well as running his own shop, and is building his own plane
between jobs. (When? God only knows....) As a result, there is usually
some major sub-section being worked on, with all the associated clutter and
fuss scattered about.

This bothered me, at first, till I found out that Keith did twice the work
in half the time of the "white floor" shop. With better results, too.

So, it's a good rule -- but not universally applicable to all A&Ps.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"