I owned both Kirk and RRS L-plates. IMO they are equally good. Sometimes one will have a plate for a model or configuration the other doesn't. If I was forced to rank them I would say the RRS versions are SLIGHTLY more nicely finished. I prefer the L-plates for versatility and the extra protection they provide the body. I do not care for L-plates that mount to the optional vertical grip on bodies that lack one. There is always a tiny bit of movement between the grip and body and the L-plate makes it even more noticeable. But YMMV.