Let me start by saying that I was in no way a Glock fan prior to being forced to carry one at work. Since then I have been sold. But IMO this is not a brand, style, or concealment issue as much as it is a training issue.
The 1911 is a fine weapon, and think this has been proven over and over. However, in a life or death situation (which is the only situation you should present your firearm), fine motor skills are greatly compromised. The 1911 has to be made ready in one of two fashions. 1. Cocked and lock and the safety lever moved to the "fire" position or, 2. Cocked upon drawing.
Both actions require fine motor skill. This can be overcome by muscle memory with extensive training and mental preparedness, but IMO there VERY FEW persons willing or able to put forth the training effort to become proficient to this level. I don't want anyone who carries a 1911 to take this as a dig. I have a great deal of respect for the weapon and persons proficient in it's use, but I can not justify putting myself, or the majority of the people that I know in this group.
The Glock on the other hand is also a proven combat / defense weapon, but the reason it is so popular is that it is an effective and reliable "dummy" gun. It is considerably safer for the average shooter because of its built in safety mechanisms that do not require the need to utilize fine motor skills. Look at target, thrust weapon toward target or acquire sight picture, squeeze trigger to point of discharge, and repeat. Muscle memory for this simple process is much easier to gain because it does not require the small muscle movements of finding and manipulating the small safety lever. Simply shooting the gun in a combat frame of mind under similar distance and carry characteristics is enough to remain proficient.
Without knowing your background, and level of training, I would go with the Glock. If you train hard, have combat experience, or other factors that may dispute some of my points, then I'd say it's a matter of personal preference. Just my opinion based on my experience.