Shoulder holsters seem a bit old school these days. You don't see them around much. Well, that's sort of the idea, if someone is carrying properly you won't see them.
They do have some good uses. If you do a lot of driving, a shoulder holster will give you much better access to your weapon. Another point the video below mentions is that if you have to get up in the middle of the night do to a strange sound, a shoulder holster is easy to slip on over your pajamas or nothing.
You don't want to skimp on your shoulder holster. It will cause you a lot of discomfort if you go cheap. The video below mentions the Galco Brand. These wear well and will work the way you need them to when you need it.
There are some things you need to know about drawing and reholster your pistol with shoulder holsters. We found a video that explains it well. Make sure you get training on this before you try it live.
Check out the video and let us know what you think about shoulder holsters in the comments.