I've been using a jailbroken AppleTV and love it. But I've been seeing so many Netflix errors regarding not being able to play certain titles (Apple's fault), and having to reboot tethered is the only way to resolve it. I'm hoping to see an untethered jailbreak in the future.
But for now, I'd like to just return it to a Factory Restore. Should I just plug it into my MBP and hit Restore, or is it more complicated than that?
You can restore through iTunes using the process you've described, or it can be done directly on the AppleTV through the Settings --> General --> Reset Settings menu.