This is great for business mail too... small company where I work was literally BURIED with spam until we moved to gmail. Since their mail addresses were "in the open" on our website for years, some of them get 200+ spams a day. Now, if 1 in 1000 passes, it's a bad day.
Also, in my private inbox, I had an VERY old mail address still redirected to gmail address... turned out that was the source of 1/2 spams (100+ / day). But those were filtered too without problem.
So far so good... not a single false detection for ham. Nothing but praise so far.
Disclaimer: I do not work for gmail. I am the genuine satisfied customer with smile on my face, from "after" picture, as seen on TV!