I agree there is a lot of hype about lenses, though with usually at least a grain of truth. The Summicron is not hype; it has been the reference standard 50mm since the Rigid and Dual Range versions came out (the first one was a bit softer). If you need a faster lens, then you have to start making decisions.
Comparing the lenses will make you crazy. Put one away in a drawer, whichever you are leaning toward getting rid of. Shoot with the other for a few months, or more. If you are happy, then sell the one in the drawer. But I wouldn't rush to get rid of a good working Leica mount lens; as you mentioned earlier, it can be a challenge replacing it later.