I suppose they have enough qualification to wipe clean those machines and install linux or at least a clean copy of windows.

On the contrary. They are qualified enough to know that there's not much they can do, whether it is Lenovo, Apple or Dell.

Windows PCs (especially enterprise laptops) are a commodity at this point. One brand doesn't offer a significantly better/worse product than another outside of build quality (which even then is usually just a factor of price). You just look for one that makes the tradeoffs (extra ports, bigger battery, etc) that fit with how you plan to use it.