I've used RRS L-plates on my cameras for several years now as I do a fair amount of tripod work using Arca-Swiss comparable clamps, and like the ability to shoot in portrait as well as landscape mode easily. First on my D7000, and then on my E-M5 with the added grip. As I've now upgraded to an E-M1, I just installed the L-plate on it. For me, it makes a significant difference in handling (in addition to the L-plate functionality). Without the plate, only my middle two fingers could comfortably fit on the grip; my pinky didn't really fit and wound up either under the bottom or in space. The plate adds just enough height that my pinky fits well on the grip, and the three fingers are much more secure and comfortable than the two were.