Just by looking at their interface, you wouldn't know about one feature that Mailive has. When you go to set up a server, it looks like you can only enter in the IP (internet protocol) Address or Fully Qualified Domain Name (FQDN) for one server.
Well, let's say you don't want to put in the IP Address or FQDN of a server, but would rather they go by your MX (Mail Exchange) DNS (domain name services) record instead. Then instead of putting in a server's IP or FQDN, you simply enter MX in that field.
Then Mailive sends to whatever server is at the top of your domain's MX list.