Hi. Was just looking for anyone that is currently using them.
If so, are you using them with a domain alias on the primary domain? I think I have found a glitch in their system and looking for someone to confirm. It would appear that when you send an email to 2 recipients in the domain using the domain alias, not using their mail server as the smtp server, the email to one of the users will bounce.
ie. primary domain is domain1.com
this domain is aliased with domain2.com
and you have user1 and user2
sending an email at the same time to email@example.com
sending an email at the same time to firstname.lastname@example.org
will usually bounce for one.
Let me know if you are using them with the above conditions.