A medium city surrounded by BFE is going to have vastly better options for outdoor recreation.

A medium or large city in a major metropolitan area will have better options for indoor recreation.

I'd personally take the city surrounded by BFE if given the choice (actually, I'd rather live in BFE and commute into the medium city).

There's definitely going to be cultural differences since Grand Rapids is in west Michigan and not eastern Germany. The food's decent, and there are a few art festivals, museums, venues and arenas. Lansing is an hour away which has more of the same. Holland is a little closer and on Lake Michigan. Chicago is only a couple hours away if you're yearning for the big city. I can't speak much about the night life but last I knew we had multiple bars and clubs if that's your thing. The only public transportation is the Rapid (bus system).