The $999 USD starting price is a bit high for a 12.2-inch FHD tablet, but the quad-core Kaby Lake-R should be a large performance leap over the current Miix 510 with the i5-7200U.
https://www.notebookcheck.net/Lenovo-Miix-520-detachable-coming-with-Core-i5-8250U-and-i5-8350U-options.244808.0.html