For shoulder holsters, I suggest the Aker rig. It comes in brown or black and the horizonal design carrys the handgun in a canted angle that is fast & smooth. The holster has a better balance & feel too. Why more US shoulder holsters do not copy that style is what I don't get. I packed a 96D .40S&W that way for 10-12 hours at a time. I'm not sure of the model name or the Aker website. www.deltaforce.com sold them in the 1990s/early 2000s.
Other great shoulder rigs are the Galco Miami Classic II, www.usgalco.com , and Bianchi International; www.bianchi-intl.com , Lawman Leather Goods; www.lawmanleathergoods.com . The vertical Lawman STU holster is leather but treated to hold up to hard use(sweat/rain/humid climates).
Some nylon & man-made material shoulder rigs are well made but they don't "breathe" they same way standard leather does.
Custom shops like Del Fatti & Mitch Rosen sell shoulder rigs too but they have long wait times.
In general, Id avoid shoulder holsters with a lot of snaps & buckles or any elastic. The rubber will wear out and break with constant use.
I like the Bianchi X-15 for my revolver. This holster works with my 6 1/2" N frame and 6" L frame S&Ws as well as a 7 1/2" Super Blackhawk. It has a spring closure which allows you to draw right through the front rather than having to lift up and out. Also have a Ross Leather vertical rig for my 1911. Nicely made but not as easy to draw as it requires a safety srtap with snap to hold the gun in the holster. The Bianchi is all day comfortable for me even with that big heavy 610 Smith.