I have both (and the Chap LW).
TLDR: Dfly
..and for me it's not even close. I carry a Dfly every day, and it's been this way for years now. It's the knife that solved my EDC.
It's the way it balances light weight and small carry size with just enough grip area to get a full, secure grip and just enough blade to get work done, and for its size it's as strong as it needs to be.
It took me a while to realize how well it fits my needs. It was the first Spyderco I bought along with a 2 or 3 others, but for a long time I didn't connect with the design, and it collected dust in my drawer for years. Only after trying out a Manbug salt and getting used to carry a clipless knife did things start to snap into place.
I loved my Manbug salt, but it's a knife that does a few things ridiculously well, but it's not the best do-anything knife, and it especially fell short on some of the electrical stuff I do quite a lot of.
With the clip removed my good old Dfly proved to be almost indistinguishably as easy to carry as the MB and a much better allround knife.
But.. the way the MB salt was able to bite into material still made me feel something was lacking with my old Dfly.
Enter the wharncliffe dfly. This is where it all came together.
Honestly I've hardly ever carried my rex45 CL Lil'Native. I bought it while I still was somewhat of a "lock snob". And I had such high expectations of this being the perfect small compression lock, maybe what the Para 3 had failed to become for me.
But no. It carries weird. It's too chubby for its length/footprint and the blade stock and subsequent weight is just more than required for the size of knife.
I'm curious to try the L'N LW, it seems to solve the issues I have with the regular L'N, but curiosity may no longer be enough to justify purchases.. idk? It's nice that Spyderco is moving in that direction and I want to support it, but it doesn't seem to answer any missing needs for me.
Regarding the Chap, I agree with what's being said. It's a fantastic knife, objectively probably better than the Dfly, but the Dfly solves my EDC balance equation in a better way.