I tried to use gnus in the past as a nntp and smtp client and I hated it. When for example I had set my user-mail-address and mail-host-address to something specific that I wanted but that gnus did not like (even though it was a valid address) it would silently replace it with some bullshit like "i-did-not-set--mail-host-address--so-tickle-me" at the from header (or was that at the message-id header? I don't exactly remember).

It also made it a pain in the butt to use a socks proxy with it. Moreover it failed to un-base64 images in emails (failing to display them), when I tried to make it open an image it would just pass the base64 string to mpv instead of bothering to un-base64 it.

I moved to mutt since then but I do want to try some other emacs clients (mostly due to the emacs and org-mode integration).