SMS texts messages are received on iPhone fine but is only forwarded to one of the Macs, regardless of the model of Mac.
I have a slick Mac Air that I take with me everywhere and a sexy iMac at home. To keep all my offline data synced, I find it easier sometimes just to restore my Mac Air to the iMac or vice versa. The restoring process is not difficult, just use the Migration Assistant with the connection to a Apple Time Machine.
I soon find out that the SMS text messages that I receive on my iPhone would only be forwarded to one of the Macs, not both. I turned off iMessage on the iPhone then enabled it again but I can only see one of the Macs displayed under the Text Message Forwarding option. For example: