Re: I still use my Gmail...
So when I sent you that legitimate email offering you a job for a millions pounds a year, that's why you never replied?
I had to shut off gmails spam filtering because too many legitimate things were being marked as spam and then being autodeleted after a while without my say so.
Having said that, gmail seems to be the best of the big providers.... At least they don't blackhole. Anyone who thinks it's a good idea to "accept" and then blackhole email without notice needs to be forced to watch daytime soaps for eternity.
I once was involved with emailing a mental health councillor at the local council. After a few important emails had gone through and hadn't been replied to for a few days, i eventually found out a week later she hadn't received them. Their spam filter provider (a commercial one that often pops up handling mail for local councils) had given a positive ACK to the SMTP convesation complete with ID.
A few trial and error test later, it seemed that the word "penis" was to blame. Instead of rejecting the email, they silently accepted it, and discarded it.
I contacted them with my findings, and the ridiculousness of the whole situation (including the flagging of medical words in emails sent to a health department) and they said they won't do anything as I'm not their customer. My non-techie contact in the council didn't know what/how to do it, so it meant that from then on, every email back and fore would be manually acknowledged.
OK, sidetracked rant there.
tl;dr Email is unreliable not because of spammers, but because of the way clueless email "techies" deal with spam.
As I said, google is one of the best. They have fierce *rejection* rules, but at least the email is rejected rather than blackholed. I'm not comfortable that the stuff they flag as spam (that has already passed their entry filters) is autodeleted after a time though.