I carried a Glock 21 for over twelve years on duty and off. I had two because I did not know when I bought the first one how reliable they really were(even though I was on the commitee that did the testing and evaluation for my dept.), that was in 1992, I got two with consecutive numbers. I alternated them one inm the duty holster and one in the locker every day. I never needed the one in the locker, even though I worked in extremes of weather from bilzzards, to freezing rain, to dust blowing so thick you could not see across the street and summer cloudbursts . I never had an issue except one when my pistol froze in the holster. due to being out directing traffic in a freezing rain, then it turned off into a blizzard, I got drenched and froze in about an hours time before my relief got to the intersection. Both my pistols retired with me. It might be noted that I did not think enough of, any of the S&W 357 revolvers I had carried prior to the Glocks to keep any of them around. I did keep my Ruger SP 101 though, it is just handy, and my Grandson wants it so it is in my will for him when he is old enough.
I have looked briefly at the xd I was not impressed, it was one of the pistols we looked at when the Dept changed to semi's but at that time it was made in hungary or somplace and we rejected it due to the fact it was imported along with several other problems.