From a fan perspective, this certainly favors the Browns. Detroit is not that far from Cleveland. And fans who otherwise were not even thinking about going to Buffalo, will have a nice opportunity to go see their team. For most of the people west of Cleveland, it is a 2 hour or less drive (Cleveland to Detroit is 2.5 hours). If I was a Brownie fan, I would certainly consider it.
As for Bills fans from WNY, for most, with the weather and distance, it is not even an option.
This move clearly benefits the Browns fan base--they will far outnumber the Bills fans on Sunday.
I used StubHiub this past weekend, it was an AWFUL experience. I will never use them again.