Camera rigs are definitely handy for mounting extra things to your camera and just in general making it more useable. Of course, if you're wanting to be subtle, just use your DSLR body on its own. But for more professional shoots, a shoulder rig is definitely recommended - it impresses your clients too!
I've actually got, it seems, a similar rig to yours in terms of its layout. Not quite as high end, but it does the job and it was pretty inexpensive as well.
It's called the Film City Camera Shoulder Mount FC-50. Link: http://www.thecinecity.com/eshop/FILMCITY-DSLR-Camera-Shoulder-Mount-Kit-FC-50.html
In the photo attached to this post, you can see my Canon 5Dmk3 (with 24-105 F4 L), Kamerar viewfinder and a wireless lapel receiver on the shoulder pad. This is my go to set up for filming interviews and piece to cam footage.
It came with many sets of rails and spare screws and connecting plates and handles. As you can see from the website photo, it's set up differently than I have it in my photo. I stripped it back because I didn't need some of the parts - but the bits I didn't use were utilised for some other things like mounting a wireless receiver and battery packs to a second monitor unit (for larger productions). I like how customizable this thing is! You can mount handles at just about any angle.
The material feels sturdy, and has supported the camera on many shoots. The shoulder pad is nice and robust and sits comfortably on the shoulder.
I'd say the main downside to the rig is the weight. After a few hours of shooting, my arms get quite tired, but it means I get a good workout hahaha. Obviously upgrading to a more expensive rig, with carbon fiber rods and lighter materials would help, but that would be more expensive. For the price of this rig, I can't complain.
I got the rig from www.thecinecity.com, who I've bought a few products from before. They seem like pretty good guys and they have loads of kit options too.
Hopefully this added to the discussion =)