I only had problems on my Kimber series II after I changed out the main spring housing, but some light filing on the inside face of the housing fixed that.
Smith had a recall on them back in '06 IIRC.
Personally I prefer NOT having the additional safety, and like Springfields approach at it by using a heavier spring and lighter (Ti) firing pin.
When it comes to the firing pin safeties, I prefer the current Colt design over the Schwartz design used in Kimbers, Smiths, and a couple of others.
Some complain that in the Colts the trigger pull is afffected with the added guts of the safety, but I can't tell the difference.
I'd suggest checking out either 1911Forum.com or m1911.org to check the threads under the S&W sections to do do some research on the subject.