I have first hand experience with both... I borrowed the 70-200 from CPS before I bought the lens. The lens was equipped (from CPS with the canon tripod mount ring) and I loved the lens enough to commit to buy it once I sent the lens back. The problem was the lens, as i found out, didn't have a ring... so I bought a third party to use when I get my lens... The ring surprisingly got to me early... so early that I had the lens for a day or two left to try out both rings... The difference is big but minimal at the same time... The canon mount locks firm.... even before you tighten the set screw... The 3rd party feel loose until you tighten the screw fully, and even at that you have to tighten it a bit just to catch. Also the difference is the canon one feels like it's a heaveir allow metal, similar to the construction of the lens itself... whereas the 3rd party, while not necessarily plastic feeling, but is considerably lighter and flimsier feeling compared to both... The 3rd party, when fully secured, is tight and secure and I'd trust it to an extent, however compared to the canon, it just is not quite the same.