rspamd has three levels of handling, depending on the spam score: (1) ham, which gets passed through, (2) spam, which does not, and (3) "not sure", which gets passed through but gets headers attached with the spam score and how the score is built up. So I get (1) and (3) in my GMail account, but all the stuff for which rspamd is confident it's spam no longer makes it into GMail.
Of course, rspamd lets you tweak the thresholds for these levels. For example, after a while I lowered the threshold for "spam", increasing the amount of stuff that gets discarded by rspamd, because I noticed that rspamd was doing a pretty good job of scoring, and the false positives I was seeing had a lower score anyway.
I'm actually not sure grey-listing is the correct term, but I noticed in my server's MTA log that Google was rate limiting me a lot because my server was sending through significant amounts of email. This was also noticeable sometimes because it would take quite some time for email to get through, which I found annoying.
Yes, you probably want to run SRS as well, otherwise GMail will be unable to correctly understand your headers. However, this effectively puts your server on the hook for any email forwarded; this is why I don't think you want to go there without also putting some kind of spam filter in place, otherwise I assume your server's reputation will deteriorate.
I don't think it has ever marked any legit mail as spam. The rspamd web UI has an overview of recent history which has the date/time, message ID and score, but there are no full headers/content for things that qualify as outright spam.
Of course, rspamd lets you tweak the thresholds for these levels. For example, after a while I lowered the threshold for "spam", increasing the amount of stuff that gets discarded by rspamd, because I noticed that rspamd was doing a pretty good job of scoring, and the false positives I was seeing had a lower score anyway.
I'm actually not sure grey-listing is the correct term, but I noticed in my server's MTA log that Google was rate limiting me a lot because my server was sending through significant amounts of email. This was also noticeable sometimes because it would take quite some time for email to get through, which I found annoying.
Yes, you probably want to run SRS as well, otherwise GMail will be unable to correctly understand your headers. However, this effectively puts your server on the hook for any email forwarded; this is why I don't think you want to go there without also putting some kind of spam filter in place, otherwise I assume your server's reputation will deteriorate.