Both experiences are fresh in my mind.

Setting up a new Mac (either OOBE or reinstall) is this:

Language
Location
Who you are
No thanks to .mac

No reboots. Quick run of the Migration Assistant[0] with the mini in Firewire Target Disk mode, wait a bit for stuff to be transferred, and job's a buck.

Setting up Windows?

Well, we've all been there. A lot. It's slow. It's painful. It's reboot-tastic.