I'll have to do an in depth analysis first, I have very little experience with NetSurf.

I would say that the plugin system is one of the things makes Dillo a bit different.

I had some ideas to do performance tests and also check how well the rendering engine works with choppy connections (while content is still slowly downloading), but I didn't do any tests yet.

There were some very old results against firefox comparing memory usage in the old page [1].

[1]: https://dillo-browser.github.io/old/memory.html

A lot more lighterweight, and nowadays it's good to have less (it has less CSS compatibility, less html compatibility and no JS).