GOOD: First off, big fan of Logitech good and I already own 2 MX Master 3's (at office and at home) - that's how much I like it. This is the same Logitech MX Master 3 that you know. Absolutely beast of a mouse with the best ergonomics, magical magnetic scroll wheel (automatically switches based on how quick you scroll), right thumb wheel, and programmable buttons.
BAD: Really disappointed here in Logitech. There's absolutely no difference in functionality in the mouse (which is good) but 2 things really stand out here. First is, all they did was change the name to "For Mac" and changed the color to Space Grey (personally prefer the matte black look of the original). Again, there's absolutely no change in functionality - nothing specific or new for the Mac that didn't exist in the original, which I currently use with the Mac (Flow is still the same, gesture buttons for Mac specifically are the same). But for the same exact price ($99), they left out the usb receiver, which offers far less latency than Bluetooth (its a dedicated channel just for the mouse vs a shared Bluetooth channel), and I can definitely tell the difference. There's a slight lag at times with the scroll wheel or when I try to move the mouse. The reason they likely did this was to save costs and because they refuse to make a usb-c version of their dongle and most new Macs only come with usb-c. But if you're using a dock or any kind or have a usb-c converter, the dongle is worth for the responsiveness alone.
Bottom line, do yourself a favor and get the original one for the same price with the dongle, and if you don't need it, at least you still have it (it still also does Bluetooth). I would have been happy had they cut the price $10 or so but why Logitech?