Here's a few of mine:
Magnum Research Mark XIX Desert Eagle .50AE
Mag springs on these are crappy. The way the spring sat in the mag from factory didn't apply enough pressure on the follower to operate the slide lock after last shot. Had to flip the spring upside down and cut off the 'tab' on it for it to operate reliably. No problems since then.
H&K USP Tactical .45ACP
No complaints here. Reliable, and waiting for the form for a Evo-45 can.
Colt 6921 Upper/6920 Lower
Permanently attached Sabre Defence Extended A2 Hider for legal 16" length via blind pin. The 6920 complete I bought new, but the 6921 upper came in less than stellar shape. I had to get the barrel exterior refinished by Virginia Arms, and it turned out great. Rail system and front vertical grip are by Knight's Armament. Grip is by Hogue, which dramatically changed the feel of the weapon in hand. GG&G flip up rear BUIS and EoTech 553 on top.
