Francis, sorry for the side-note above on focus shift, but it may not be an important factor depending on how you like looking at photos and your criteria for what will ruin one.
I've used both, and I don't think you'll be disappointed with either from an image standpoint. I liked the short throw on the Nokton and the flare resistance. It's noticeable bigger, especially with the hood, but my copy rarely flared so I didn't use the hood. The only irritating thing was some gritty-ness to the focus ring right out of the box, but that could be dealt with. If lens size isn't a problem, the Nokton is a dynamite deal.
The 35mm summilux asph is way more lens than I could ever effectively exploit, and if you own one long enough (I'll never sell mine), its price, over the long term, isn't that big of a deal.
I've used both, and I don't think you'll be disappointed with either from an image standpoint. I liked the short throw on the Nokton and the flare resistance. It's noticeable bigger, especially with the hood, but my copy rarely flared so I didn't use the hood. The only irritating thing was some gritty-ness to the focus ring right out of the box, but that could be dealt with. If lens size isn't a problem, the Nokton is a dynamite deal.
The 35mm summilux asph is way more lens than I could ever effectively exploit, and if you own one long enough (I'll never sell mine), its price, over the long term, isn't that big of a deal.