Upload & Sell: Off
I use both 1D series cameras, and 5D series, and depending on what lenses are mounted, it can get heavy. Not to disrespect any of the Optech fans, but I have Optech and the Upstrap, and the Upstrap wins for me.
The Upstrap is designed so it doesn't move at all when on your shoulder. It is very positive, and feels like it is locked onto the load. I have never used any other strap that holds onto my shoulder as well.
The Optech is nicely made, and a little more comfortable to wear, but even with its anti-slip it still moves around more than I like. There is also an elasticity to it-it stretches a bit-and I don't like how that feels when walking and moving around.
The Upstrap comes in several different configurations, and if you need the quick release, it is available that way.