I bought my 1991A1 Compact back in '97. The first thing I had to do was dump the factory mag!
The store I bought the gun from has an indoor range so I decided to shoot it before taking it on home. The gun was a jam-a-matic when I used the factory mag. I went and bought 2 Shooting Star mags and resumed my range session. 100% reliable!
I have since modified the gun as follows:
Wilson guide rod and plug, Wilson Thumb safety, Ed Brown beavertail, checkered front strap 30 lpi, short trigger, S&A checkered mainspring housing, Hogue checkered Kingwood grips and a Novak rear sight.
Recently, I had a bit of a problem with the firing pin sticking forward and allowing the firing pin stop to drop down and tie up the gun. I was shooting +P ammo in rapid fire drills. I've got a Ed Brown firing pin stop, a 24# recoil spring and a extra power firing pin spring to go in the gun this weekend. That should fix the problem.
Bascially, I very happy with this gun. It wasn't out of the box reliable, but a simple magazine change fixed that. Of course, your mileage may vary!