After two years of using Fastmail as my primary account, in my effort to de-Google in 2022, spam recognition at Fastmail seems to me to be on a par with Gmail, if not better. I still use both.
I use Fastmail for 5+ years now. Initially I feared that the experience would be worse than Gmail (with regards to the Web UI, to spam filtering, etc). It is not. It really is much better!
Which plan are you on?
I use the standard plan.
I really have no qualms about Fastmail spam handling either. It's fine; don't let that stop anyone from switching away from Google.
Agreed, Fastmail is pretty good at spam filtering. My Gmail account is pretty much full of spam nowdays which seems to suggest Gmail's spam filtering isn't that great.
What makes me really mad is that I mark a sender as 'not spam' over and over again in Gmail and where does it keep going? Spam. I have a bunch of system emails and I can't convince Google to just give me my damned mail.
I love it. I can sync my Gmail to it seamlessly as I slowly transition all my accounts to my new email address.