That's pretty good. I have no doubt that Gmail spam protection is better than my self-hosted SA protection. For me, independence from a somewhat suspicious large company for something as important as e-mail is worth it.
I have a gmail honeypot where I fetchmail junk email straight to my junk folder and have a scheduled sa-learn cronjob. Ever since I started this I essentially stopped getting junk email in my selfhosted inbox.
I also have dovecot set to learn Ham every time I file an email from the inbox to a folder for good measure.
I also have dovecot set to learn Ham every time I file an email from the inbox to a folder for good measure.