I decided to give shoulder carry a try, because when I wear my Serpa holster on my hip, the grip of my gun sometimes gets caught on the edge of chairs when I go to sit down, and sometimes makes a "thud" noise. I didn't want to buy a whole new holster and rig, so I bought the Blackhawk Serpa shoulder harness for my G19's holster. Shoulder carry for me seemed uncomfortable at first, but after wearing this thing all day, I started to get used to it.
I practiced drawing my pistol (unloaded of course), and it is a bit slower than when I draw from the hip. I did buy two Blackhawk magazine holders to go on the opposite side of the rig, and thank goodness I did. It distributes the weight evenly so I don't become sore from having added weight on my left side. It conceals under loose fitting button up shirts ok, but still prints a little. I figured hardly anyone will pay attention unless its someone actively looking for people who are packing.
Overall I'm fairly pleased with this shoulder rig, and I can still mount my other Serpa holsters on the same harness which is nice. It also makes driving alot more comfortable because I don't have my pistol digging into my side when I sit behind the wheel, and if there is ever a need to draw while I'm in the car, shoulder carry makes it easier.