Not sure of what your uses are for (nor do I really care--It's not my business), but before spending money on a shoulder holster, do some research on the clubs you wish to join. Most (if not all) clubs prohibit the use of them, because, when drawing your gun, you will sweep a large area around you.
I've used a shoulder holster once, while stateside and I found it uncomfortable and cumbersome. I'll take a belt holster any day of the week