I have configured Postfix to be responsible for subdomain.example.com (google apps is responsible for example.com so I didn't want to mix the two).
As I mentioned in question title, SPF and DKIM always pass when I send mail locally from that host (
$ mail email@example.com), but mails still end up in Spam folder.
The only thing missing is reverse DNS setup for subdomain.example.com and IP it's sending from, but I figured it won't matter, since SPF includes a:ip.add.re.ss, and since SPF passes...
Any ideas what else could I do to get them into inbox?
UPDATE: problem was instantly resolved as soon as Amazon removed my IP from Spamhaus PBL (see answer below).