Although I like both of the above, they have different characters. The RY4S UE has tight bass, decent soundstage and excellent clarity, but it is a bit cool and the mids (vocals) are a little thin. On the other hand, the EMX500S is overall warmer and darker, and although the soundstage is bigger there is less definition throughout the FR.
Better than both of them IMO is the Snow Lotus 1.0. It has most of the best aspects of the other two, the mids are more natural and forward than both, and overall is the better all-rounder to my ears.