Down Side:
If there are kids, there will be drawings on the walls, and cornflakes (with milk) stuffed down the back of the sofa. (Just like in non rented houses).
Up Side:
No large alcohol fueled parties until 5 in the morning. So no complaining from neighbours and no broken (as opposed to merely dirtied) furniture.
May be likely to want to stay a while.
Depends on the accommodation -
what sort of finishes do you have? Lots of carpets and a fabric living room suite? Then I'd decline.
Laminate, lino and tile floors with leather/ette furniture - then I'd accept.