This subject has really been overworked. However, here's an example of what makes life interesting.
Usually, the side with the device is considered the obverse. But how about when the device is one one side and the issuing authority is on the other?
Take a look at this rare, old token used to pay workers removing snow from the tramway tracks in Bucharest, Romania. The authority SOCIETATILE DE TRAMVIE BUCURESCI and the value 1 DI are one one side, while the other side depicts a old tramcar and SERVICIUL CURATIREI ZAPEDI, that is Snow Removal Service. Photos: C. Cretulescu.
Personally, I would still stick with the authority side as the obverse.