Ambi controls, at least the safety, are useful when you practice your weak hand shooting which, of course, is a regular part of everyone's practice routine. If you shoot IDPA and such, an ambi safety lets you shoot from an on-safe condition during weak hand stages. Also adds another safety layer to transfers among hands between strings, during which a lot of people seem to instinctively put their weak hand trigger finger in the guard, (probably because that's a more natural position than with the weak side index finger extended along the slide or frame). SO's seem to miss this. And, if you find yourself with a sudden and lengthy loss of use of your strongside arm, as I did last year, you will soon learn to appreciate ambi controls. slide lock included. That episode, in fact was the primary reason I went with the 85 Combat. Ambi controls do add slightly to width, but I've found that a number of off-the-rack holsters are made to fit either the 75 or 85 anyway.