I take issue with that.
The Colt factory is turning out excellent work, and their prices and turn-around are quite good.
NO ONE knows more about it than the Colt plant.
Cylinder & Slide is EXCELLENT, BUT.....prices are HIGH, and due to the volume of work, you'll likely wait for quite some time. (Months)
C&S is more for true custom work, not ordinary repairs.
Other options are:
Pittsburgh Handgun Headquarters
1330 Center Ave.
Pittsburgh, PA 15229
(412) 766-6100
PHH used to be the Colt factories over-flow center for warranty repairs. Turn-around and pricing as about as good as the factory. Quality is VERY high.
While I haven't seen his work, and can't comment on it, Grant Cunningham gets good reviews from customers:
http://www.grantcunningham.com/