All so called QR mounts are ugly in that they still leave "pads" or bases on the rifle. The cleanest are IMHO the integral system used by Ruger and BRNO (on the ZKK rifles...or their rimfire models) where the receiver itself is machined to be the actual mount the two rings clamp to.
I've owned or shot rifles with Holland & Holland side mounts, Suhler (German) claw mounts, British No4(T) side mounts, Apel mounts and American Redfield "turn in" mounts.
For smooth lines when the 'scope is detached the BRNO way beats them all and Ruger is second. Next are Suhler claw mounts. Worst are, equally Apel and Redfield "turn in mounts".
Holland's and American and continental side mounts are somewhere below or above Suhler mounts. It is just a shame BRNO's excellent system became obsolete because the dedicated Zeiss Jena ZF4 and ZF6 'scopes ended production.
But for clean lines, true QR ability and return to zero BRNO's system was the best. And the least complicated. Ruger's is the nearest we have today. Enabling TRUE multiple 'scope ability on one rifle.