attention opinion only!
i have no experience with any 50mm summilux, but i used to own the noctilux for quite a while, and i loved it for the pictures it painted - but its dimensions made it a "heavy" friend.
finally, i sold and got me a ZM c-sonnar instead. easy to carry, about the same way "need to get used to" as the noctilux, and again so beautiful picture painting. i know the c-sonnar is not for everyone, but it may be worth considering.
end of opinion.
cheers