My problem with Gmail is the false positives. (Or is it negatives?) They routinely send too much to the spam box and others tell me they have the same experience.
The worst is when they take email from one Google hosted ___domain and send it to spam in another Google hosted ___domain, even though the email didn't leave their network at all.
Still, I agree that the overall level is pretty good and hard to duplicate.
> even though the email didn't leave their network at all.
FYI gmail treats all of its children equally. Mail from one Google user to another is subject to the exact same treatment as mail received via SMTP (and, indeed, Gmail sends traffic to itself over SMTP). If you study the headers of messages in Gmail, you can form a picture of how they allocate and use the virtual IPs.
The worst is when they take email from one Google hosted ___domain and send it to spam in another Google hosted ___domain, even though the email didn't leave their network at all.
Still, I agree that the overall level is pretty good and hard to duplicate.