Just a quick note on Gmail. It's not just a mail server, it also filters and classifies emails better than any other product on the market.
No other company has that kind of volume of data and heuristics
No other company has that kind of volume of data and heuristics
The big issue, is your much talked about data and heuristics are unreliable. Since Google changes their software or algorithms without my permission, I can't rely on any of them.