I just purchased the Logitech MX Master 3 after using the Logitech MX518 for 12 years. It's slightly different but still pretty ergonomic. I have small hands and it fits ok, if you have larger, or normal size, hands it should fit really well.
Casey Grimley
AC24
iMac Pro (2017) - macOS 10.14.6- 3.2GHz Intel Xeon W - 32GB RAM - Radeon Pro Vega 56 8GB