It turns out that the Apple Developer Transition Kit and the A12Z Bionic stand up well against the Microsoft SQ1 in the Surface Pro X too. With both powered by eight-core custom ARM chips, the Transition Kit has the edge in single-core performance, while the Surface Pro X wins out in multi-core work.
https://www.notebookcheck.net/Geekbench-sees-the-ARM-based-Apple-Developer-Transition-Kit-putting-on-a-good-showing-against-the-Surface-Pro-X.478677.0.html