Question Lenovo ThinkBook Factory Reset

Having done both, I would agree with Master Colif. Both are a path to the same place, but using the Windows Media Creator will likely take less time. The Lenovo Recovery Service installs a recovery image of the original OS install, which is a lengthy process unto itself, then needs to be updated. OTOH, once the WMC has completed it's work, you will need to install the Lenovo app, which will download and install all the Lenovo specific drivers.