FWIW. we stayed at Suiran for 5 nights (Presidential Suite), at the RC Kyoto for 2 nights (Kamogawa Suite), and had lunch and toured the FS Kyoto in May 2018.

The RC to me feels far more intimate, more authentic, and with a true Japanese sense of place than the larger and much more corporate feeling FS. The aesthetics of the two couldn’t be more different. The RC Kyoto clearly is about Japan; until you step outside into the FS garden, the FS could be anywhere in the world. But @BESVISOR is accurate in that the public spaces at the RC are darker and more subdued whereas those at the FS are lighter.

As everyone compares and contrasts those two, and even as much as we loved our stay at the RC Kyoto and agree that it may be the finest RC anywhere in the world, it actually is the Suiran property that make us most yearn to return. If one prefers the normal Western hotel feel and amenities, then the RC or FS both will serve you very well. If one wants an even more authentic hybrid ryokan/Western hotel experience, then the Suiran outdoes both the RC and FS without much effort at all. Suiran is that rare gem of a boutique luxury hotel that beautifully combines the true sense of place with some Western luxury niceties. I’d recommend one of the upgraded larger room types for this audience, though!