Here’s a summary of what you should do to prepare your Macs right now for the possibility of theft. It won’t eliminate theft but it will greatly reduce the damage from such events and make it more likely that your device will return to you.
Personally, I don't bother with tracking software, but I have good insurance (well, I think I do...), and very regular backups, both onsite and offsite.
For me, FileVault encryption of both internal and backup drives is essential. It's trivial to setup, you don't need to reformat the drive or do anything special (tho leave it overnight if you can for the main system drive), and it works for external drives too. I've noticed no performance difference on the retina MBP SSD, or on external spinning rust disks.
And backup. Please.