I believe NGINX's caching is as efficient, if not moreso, but it is less flexible. The tools available to you in Varnish's VCL are substantial, plus you get ESI support - something NGINX lacks.

Also selective cache purging is a paid feature with nginx.

If you're using the filesystem backed cache with nginx, selective cache purge, stats, etc, is a fairly trivial scripting task.

Agreed, There is also an OS alternative which essentially mirrors the functionality of propriety nginx cache purge: https://github.com/FRiCKLE/ngx_cache_purge

Hence you can just build it with your standing nginx binary reducing the need for miscellaneous scripts.

thanks for the info/link!

I doubt there's a notable performance difference, and it's a bit of apples and oranges unless you front varnish with something that does SSL for your benchmark. Not many use cases for plain http caching anymore.

Varnish does likely have an edge with flexibility and expressiveness around configuration, since it's a single purpose tool.