There have been numerous discussions about the SMC vs Pacific Omega rings. IIRC they were both ample for suspension purposes. Opinion seemed to revolve around the fact that PO seemed to weigh more and have a wider radial curve to the ring. That plus REI was continually selling out of the SMC rings. There were even rumors of REI employees grabbing and buying the rings before they were even stocked to the floor.
The relative weights and size of SMC vs PO rings have probably not changed. Presumably availability of the SMC rings have stabilized. I remember no such discussions concerning the Petzyl. They may have been relative new comers. These discussions were several years ago before whoopie slings replaced the webbing/ring buckle suspensions as the coolest toy of the season.