Yes, they should move to something with a better reputation, like Hotmail or Yahoo! ;-)
Mind you, I did recommend an AOL product to someone recently, AOL's free AV program, which uses the Kaspersky engine (along with AVG and Avast too).

I'm quite a fan of Avast!, although dr_walpulgis, who recommended it to me, is now plugging AVG.

Couldn't agree more; our official corporate line is we don't exchange mail with AOL (even if a member of staff tries to send stuff to aol, they hit a rule in the rule access that causes sendmail to reply "550 Cannot send mail to aol.com").

One of the suits complained he couldn't get company mail forwarded to his AOL account; I simply told him it was unprofessional to use AOL and it's not supported.

This is good to hear! I'm intrigued about the problems AOL have caused - I've never relied upon a non-Unix network, so I've been protected.

Many of the problems I've heard of relate to their incoming spam filters being over-zealous. Apparently AOL users have a button on their mail client to tell AOL's spam filters "this is spam," but instead of using the information on a local per-user filter they use it on the AOL-wide filter, such that if enough AOL users click on the button when they receive messages from a particular ISP, AOL block all messages from that ISP. Where this really causes a problem is when there are legitimate subscriber-only mailing lists sending out via an ISP, but AOLers can't be bothered to unsubscribe properly, instead just clicking on the "this is spam" button every time they receive messages from the list.

I remember one US company which wouldn't accept any mail which didn't end ".com", refusing to believe ".co.uk" was a legitimate address. It was a few years back, mind.

On this occasion it's an issue with overzealous spam filters again -- I'm sorely tempted to tell this particular client that I'll refuse to attempt to sort it out next time the problem arises.

And also persuade all your customers and suppliers to move away from using AOL addresses.