Btw..., what's more connectively reliable, Bluetooth or Unifying Receiver?
A UR is more reliable inasmuch as they do not suffer the usual bluetooth connection shenanigans but in the end, decision depends on needs
Bluetooth is very convenient as it does not use usb ports and same mouse can be used on multiple devices.
A UR is limited to one device.
However bluetooth devices do not work in winpe mode. For a laptop, this is not such an issue as you can use a trackpad. For a desktop, you would probably need to connect a usb corded mouse.
On a desktop, a UR is probably better as you generally have lots of usb ports.
For a laptop, I personally prefer bluetooth as I have three laptops (main, backup and travel). I do not need to worry about whuch mouse is connected to which ur. Bluetooth mouses (mice?) are totally interchangeable. Like most users, I have a usb corded mouse as backup.
So like most things, choice depends on personal needs.
This is why this sort of poll is completely pointless as answers are totally random, and rarely cover permutations.