OEM vs Retail

Both keys are genuine, lifetime and activate online. The difference is what happens when you replace your computer.

OEM Retail
Genuine and lifetime Yes Yes
Online activation Yes Yes
Move to a new PC No, tied to the first PC Yes, when you stop using the old one
Price Lower Higher
Best for Keeping your current PC Planning to upgrade your PC

Which one should you choose?

If you do not plan to replace your computer, OEM is the better deal. If you plan to change it, Retail lets you take the license with you.