I've never had a problem with Spamhaus, it's straightforward enough to get removed from the list if needed. It's way worse dealing with providers such as Hotmai

I've never had a problem with Spamhaus, it's straightforward enough to get removed from the list if needed. It's way worse dealing with providers such as Hotmail and Yahoo who arbitrarily block mail. I'd argue that 99% of businesses are better served letting a third-party deal with marketing and transactional emails and only use outgoing SMTP for their own emails.