I'll second Scatterbrained's endorsement of the OP/TECH uni-loop system.
I use a 1DMK2 that I purchased second hand on the original OP/TECH strap that a professional sports photographer used for 60000 images, many with a 70/200f2.8 or 300f2.8 attached to the body.
It shows absolutely no wear at the attachment point on the camera lugs, zero, zip, zilch. You can definitely trust OP/TECH straps and for that matter all of their gear. For the money expended the performance easily meets or exceeds that of similar systems costing considerably more money. OP/TECH gear is excellent stuff by anyone's criteria.
EOS Elan, EOS7NE, EOS 40D, EOS1DMK2, Canon 15-85 IS EF-S, Canon 28-80 USM, Canon 28-105f3.5/4.5 USM, Canon 70-210f3.5/4.5 USM, Canon 70-300f4.5/5.6 IS USM, Tamron 19-35f3.5/4.5, Tokina 80-400 ATX 11, Sigma 150-500 OS HSM, Promaster 7500DX, Benro A3580F