The layout of tracks range from basic to complex, though all share the same high end visuals. TrackMania United doesn't go for an ultra realistic look, instead opting for arcade-styled visuals. Some cars resemble real cars while others look like they were driven out of a concept gallery. Tracks are built around lavish views of cityscapes, forests and islands and feature all sorts of glitz like neon lights and sunsets. Some will even show time of day changes. The only downside are the in-game ad that are posted in every track. I personally don't mind ads, though it is worth mentioning if you are the type that despises the trend.
Music matches each tracks setting perfectly and helps to set the mood of each race. This is to be expected, except that you (hopefully) spend so little time in each track that it can be hard to grab you. It wouldn't hurt if the sound effects were a little more prominent, but overall they are good.