How to quickly change user profile in Google Chrome?

Windows and Linux:

Ctrl+Shift+M then ▼ then Enter then ► or ◄ until you reach the user you want.

Mac OS:

⌘+Shift+M then ▼ then Enter then ► or ◄ until you reach the user you want.

Note

On Chrome 78 this keyboard shortcut opens the profile menu and focuses your previous used profile, so after you invoked the menu it's enough to hit Enter to quickly switch from one profile to the other.

Chrome now has a "People" menu. If you have two profiles, say "Work" and "Personal",

go to System Preferences -> Keyboard -> Shortcuts -> App Shortcuts
click the +
choose "Google Chrome.app"
add one keyboard shortcut for "Work" and another one for "Personal".

Below are instructions to setup your own quick shortcuts for Mac OS X in case you consider Chrome's default combination of keys too long for a "shortcut".

Part 1.

Launch Chrome
Click "Preferences" in "Chrome" menu in the top bar. You should see more than one user profile in the section People. For example, "Work" and "Personal" or "Work" and your name.
Click on "Personal" or your name and click "Edit" below it.
Rename it to "Gpersonal" or something else. I am not sure why this is needed, but it worked for me only after renaming it.

Part 2.

Go to Mac OS X Settings You can do it via Apple icon in the top left corner.
Go to "Keyboard" > "Shortcuts".
Choose "App Shortcuts" in the left pane.
Click "+" in the bottom.
In "Application" section choose "Google Chrome"
In "Menu Title" type first profile name. For example, "Work" without quotes.
Choose a keyboard shortcut, for example, "Cmd+Shift+,".
Click "Add".
Click "+" in the bottom.
In "Menu Title" type first profile name. For example, "GPersonal" without quotes.
Choose a keyboard shortcut, for example, "Cmd+Shift+.".
Click "Add".
You can go back to Chrome now and try new shortcuts.