The subject line of this message is clearly wrong.
255 of the 821 subscribers to this mailing list use @gmail.com mailboxes.
If there were a problem with gmail, it would have shown up long ago.
I have a bit mixed feelings about it. As a coordinator I get regular mail from gmail users and often experience that my replies do not arrive or get marked as SPAM. I get reminders about requests that I have already processed, and sometimes a message "oh sorry I found your reply in the SPAM folder".
At first I blamed my use of an @amsat.org address, and also using that address as a From: address in my replies. Due to the SPF record on amsat.org it can be expected that such use leads to marking of mail as suspicious.
So I switched to using another alias service (@vrza.nl being offered by one of our amateur radio societies), but the situation did not improve. I still get reports of my mail ending up in the SPAM folder at gmail. But the vrza.nl domain has no SPF record.
Apparently there is some relation to the user receiving the mail. Some users receive all my mail without problem, no matter if sent from @amsat.org @vrza.nl or another source. Others report that it is treated as SPAM for each of those.
Not being a gmail.com user myself, I do not exactly know what features it offers for whitelisting or other special treatment of mail, or maybe what it learns automatically. It could be that sending back and forth several mails eventually leads to an address getting on the whitelist automatically. The same could be true for mail server IP addresses (like a mailinglist server), and it could be that knowledge built in the past also affects the results of new SPAM criteria added later.
It is all a bit opaque, and when you want reliable and predictable mail service, using those mailservices certainly is not the best choice... or at the least check the SPAM folder regularly. (but I have also received reports of mail being dropped and not placed there)
Rob