I have exactly the same two brands as ShanghaiDan! Schuberth is the best IMHO of course. Pricey but top shelf. RPHA was my favorite until I made the plunge for the C3. RPHA might be a bit cooler but both are hot down here in FL in the summer. I have had a bunch of different helmets over the last 40 plus years and none come close to the C3 Schuberth.
Dan is also right on with it being quiet. Much quieter than RPHA and RPHA is pretty quiet. 3dB increase is twice as loud if I remember right.

Good luck with your search.
WEG