I have the FDA EV1M, which of course is for the RX1 and the RX100M2 only, as far as I know, so not precisely what this thread is concerned with. However it and the EV1S are essentially identical, and my experience of the xxxM is that it functions beautifully, with an amazingly clear, (and non-laggy) picture. I mainly stuck to the main screen for indoors work, or outdoors if it was not bright, but in bright conditions this really comes into its own and lets you compose your picture and see exactly what settings you are on. Expensive, but I never regretted buying mine- it really expands the functionality of the camera.