I have three...
... one that I keep at work, because it's easier to deal with in the cockpit than anything at belt level. It's a vertical carry from shoulderholster.us .
http://shoulderholster.us/
I have another of theirs at home, that I use for my S&W Mountain Gun.
On the plus side, the shoulderholster.us rigs are pretty comfortable, and conceal relatively easily. They are also vertical rigs, which is good for work, because horizontal carry is banned. On the minus side, they are not set up for carrying any spare ammo.
My third shoulder holster is a modular rig from Sam Andrews, the "Monarch."
http://andrewsleather.com/monarch.htm
The Monarch has soft, wide shoulder straps. It also has a stabilizer band around the back, to prevent the holster from moving around when one leans over, and minimizing the pounding if one runs. Also on the plus side, it's highly adjustable; and it's modular (I had mine set up for a duty pistol, but since the horizontal rig was banned, Sam is sending me a Commander holster component; I'll probably get a Browning HiPower holster next year, after I get my BHP back from Novak; I have magazine holders for both single and double stack mags), so holsters and mag holders can be switched out.
One advantage to shoulder rigs that doesn't seem to get posted all that often is this: You are very unlikely to hear of somebody forgetting their pistol on a rest stop toilet tank, if they were wearing a shoulder rig.
Not that you should hear of that happening with belt rigs, but unfortunately it happens. (Tucking a 1911 inside a boot top can be a bit distracting, too.)