I have been carrying my XD40SC for 2 years and have taken four advanced tactical courses with it. I have over 7500 rounds through it and it has been dead reliable. I have dropped it, dived into a lake and the Gulf of Mexico with it on along with countless other activities. I have drawn it once to stop a forcible felony being committed on my brother (who was anti-gun BTW). It has never let me down. My family trusts their lives to me and I trust our lives to my XDs. I have 4 XDs.
I am in the process of testing a new XD 45 Compact. Once I have a couple of thousand rounds through it and have dragged it through a couple of tactical courses, it will replace my XD40SC. I chose the XD because I used to carry a CCO-sized 1911 and the XD felt more natural to me.
I also have an XD-m. Although it is too large to CC for my frame, it is a great gun. If they make a non-competition oriented version of this with straight sights and in compact form, I'll definately field test it for carry.
I think the Glocks are good guns for many people and many people choose them for various reasons. I personally don't like Glocks for my reasons as I have seen enough Glock failures and anomolies during hard tactical abuse. Also contrary to some people's experience, I think Glocks feel cheap compared to the XD. As a range or nightstand gun it might be fine but for what I do with them, Glocks are not for me. I might get flamed for these comments but that is my experience. Other people may have different experiences.
As for comments about grip safety on 1911s and XDs, I'll echo what one of my instructor said, "If your grip doesn't depress the grip safety enough to fire the gun then you don't have control of your weapon and you'd be negligent to pull the trigger at that time." I have tested this theory and I would have to be holding the gun so improperly that I couldn't pull off a double tap without posibbly dropping the gun. I have never had a failure due to improper grip of the gun from a draw. Again that is my experience.
As for ammo, choose the gun that you are most comfortable shooting defensive ammo with. There has been more ballistic development on the 9mm than almost any other round. The new 9mm stuff is quite good. If cost of ammo is an issue, 9mm practice ammo is very cheap compared to .357Sig.40S&W or .45ACP or GAP. Based on shooting comfort and accuracy of DEFENSIVE ammo, I prefer .45, .40, 9mm in that order.
Good luck.