Look, Kraftwerk music is pretty unique, and you either "get" it or you hate it. The music is one remove from minimalist and much like on the classic "Autobahn" is a study in recursive examination of simple interlocking themes. It isn't music for everyone.
As another reviewer with more insight has said, this album represented the point where Kraftwerk were solidly committing to the electronic instrumentation as the vehicle for their vision. Synths are doing all the work on this album without the acoustic and electric instruments that were occasionally in evidence on "Autobahn".
For me the album has many high spots, but I love the audio pun that extends the idea first tried out so successfully with "Autobahn" - Trans Europa Express/Metall auf Metal/Abzug. A musical work that recapitulates the monotony of a transcontinental train journey on a modern train; classic, funny, clever.
That said, I was seriously worried for a while that their next release would be "Watching Paint Dry", until I realized that both Autobahn and TEE had the idea of the tedium being in order to go from somewhere to somewhere else, enabled by modern technology (hence the choice of instrumentation).
In this day and age the analog electronic sound might be too simplistic for ears weaned on rich digital/sampled electronic soundscapes. On the other hand, the cost of finding out has fallen.