Just to chew on...I was looking for a good off duty piece and narrowed it down to the XDS and Shield. I shot both, from other guys in my agency, both shot very well and I liked the way the XD felt for the 3 mags I put through it.
That being said, my partner said he had had numerous failure to fires with his .45 XDS. What he noticed is, on occasion, the slide will not go fully back in to battery, causing a light primer strike or no strike. He guessed about every third to fourth magazine, at least one. He has since called and sent it back to Springfield and they tell him it is a grip issue, not a gun issue. It will subside with time...
My partner has since sold his XDS, as they will not do anything about it and purchased another subcompact.
Personally, off duty or backups need to go "Boom" EVERY time the trigger is pulled, regardless of how many rounds you have put through it. Have not heard of the same problem in other caliber XDS's though.