Those looking for great concealment should look at this type of holster for long term carry.
http://glockstore.glockstore.com/usa-iwb-holsterThe advantages to this holster versus pocket or some kind of clip system is that it protects the wearer from sharp edges, protects finish of weapon from body oils and lint etc. It also protects your clothes from premature wear. It also aids in concealment by making it harder to print through clothing. This holster also allows you to tuck in your shirt and still hold your weapon securely,no fear of having the weapon work it's way out and fall out.
It does make it easy to draw weapon without snagging on clothing and you can re-holster your weapon after firing without burning yourself.
The holster is made for many different models including various 1911's.
many female law enforcement officers use something like this over a purse unless wardrobe or situations dictate otherwise, it is too easy to loose control or access to a weapon if in a purse versus on the person.