I have a Delta Elite that had a few hiccups when I first got it but now after a few hundred rounds and a lot of cleaning and oiling it runs like a champ. I've gone throng a few different ambi-safeties trying to find one I really like. I finally spent the money for a Wilson Combat bulletproof tactical ambi-safety and I love it.
My Sig 1911 Extreme has never had a hiccup through about 300 rounds and it came standard with ambi-safety very similar to the Wilson Combat bulletproof on my Delta.
Glock 20, Colt Delta Elite, Sig 1911 Extreme, Norinco SKS-D, AK47, Marlin 795 .22LR, CZ 452 LH .22LR, Colt M4 .22LR, S&W M&P-15 Sport, Remington 700 SPS LH 300 Win Mag, Winchester 1300 Defender 12ga, Winchester 1300 Black Shadow 20ga