I have been using nginx in the past, but I have been meeting with a little friction in managing virtual domains and https.
In the future I would like to try Caddy, as it has simpler configuration and it has a few quite useful modules, like integrating Caddy with git and Hugo, and of course automatic SSL management.
It is not as fast as nginx, yet. So, for really busy sites (100s simultaneous users), nginx is still better.
Notes form a site that uses Caddy:
Although I do not manage WordPress sites, Caddy works with PHP-FM:
Serving owncloud with caddy (it may be of help for seafile):