The keyboard shortcuts to change the brush size and hardness are the same on both Windows and Mac. They are easily customizable via Edit > Keyboard Shortcuts and then selecting Tools and scrolling down.
There is also a Heads Up Display (HUD) method to set all of these (plus color too!). On Mac, hold down OPT+CMD and click to do this. On Windows hold down ALT and right-click to do the same. Add Shift in too and you can set your color. Hit the Spacebar and you can isolate the color, so you can play with the Hue.