I can summarize my feeling with Caddy as it's probably a good choice for solo developers with a handful of sites on a single VPS that's not terribly important. If you have something really important, I would look elsewhere.
Caddy used to put non-removable advertisements in the response headers. (That one got such a bad backlash that they backed away...)
Caddy refuses to cooperate with OS packaging teams. It reeks of self-importance. It's questionable whether caddy is really FOSS with its odd licensing arrangement.
I've seen a number of backward-incomptatible updates that break config files from point-upgrades.
Caddy EXITS with error on boot if any of its HTTPS enabled sites fail to get certificates.
Which puts your webserver in a fragile state: the server may serve happily for months (with a hidden cert error) until you restart the service. Then all your sites are down.
Migrating a live website from one server to another is (or was, until recently) quite un-supported and hard to do with zero downtime. See caddy needs DNS pointed at it before it can get the cert -- but it can't start serving pages until it has the cert.... Just not acceptable story in a high availability environment.
I understand that now caddy can share its certs with a pool of other workers which may help migration processes moving forward.
I may be bitter about this as it caused a lot of damage and downtime for my business. Not inclined to ever touch Caddy again if I can help it.