I am getting a replacement Mac today and I am concerned about the reliability of the Migration Assistant in High Sierra. Both times I've used High Sierra's Migration Assistant there have been timeouts on several new machines (2016 and 2017 MacBook Pros), resulting in me having use Target Disk Mode on the source machine to get the transfer to complete.
I believe I lose a little bit of data every time I migrate from one Mac to another using Migration Assistant. Over time I have found empty directories in my data that I'm absolutely certain weren't empty one or more migrations previously. I believe the issue may be related to inadequate permissions when trying to transfer the files.
With that being said, what permissions does the target machine have using Target Disk Mode via Migration Assistant? Is using Migration Assistant via Target Disk Mode the safest way to ensure ALL my data is transferred from my old Mac?