Curious to know if ppl use the Rspamd service and is it a valuable tool on OPNsense?
I use Rspamd on my personal mail server (not OPNsense) and it's a great product and works well.
I use it too .. not for hardcore business .. but it works quite ok.
Which MTA are you using? Is this for personal or business email?
I'm using a Zimbra Collaboration Server (which has Postfix as it's MTA) since 2005 and with Rspamd integrated in it quite successfully for the past three plus years, no problems for me and lightweight compared to the alternative like Spamassassin.
I use this for business and personal mail but it's still a lightly loaded server. Some other members of the Zimbra forums also use Rspamd in a business environment.
I use rspamd on my root server with postfix and it works great - 100% catch rate so far together with a strict postfix precheck.
My wife and I have Gmail accounts. Prolly half her mail is spam. I am considerably less, maybe 10%. Google does a horrible job of spam protection, which is why I was considering rspamd.
In this config should I go through the effort to setup a MTA and rspamd?
I do not know your goal but a MTA is no solution if you mainly use gmail. postfix/rspamd works if you have your own domain and not for an upstream mailbox.