Wouldn't tell anyone to go to Mannheim for a citytrip, but should you ever need to go there for work, or be in the neighbourhood, or need a place to spend the night, I would definitely recommend Mannheim! It's a very green city and a great place to take a long stroll to take in the surroundings, for example on one of the many lush walkways next to the river Neckar or in the many parks. In one of the smallest parks, close to the train station, the one around the Wasserturm, there was a colony of the cutest, photogenic rabbits. Rabbits in the city center automatically improve the atmosphere and my rating of it. There's some nice architecture as well and it's a fine place for shopping.