There is something about Takemitsu's orchestral work, that makes the music very "visual". This set is a good value introduction and the sleeve notes (even with the typo errors!) translated from the composer's own words, gives an invaluable insight to accompany the music.
If you are deciding whether you would like the music, before buying the CD, I would say if you like Debussy and some of the early Modernist composers, then you will find sonorities related to that range of early atonal and serial composition, but with more similarity to Debussy in terms of atmosphere and harmonic colour. I sometimes describe Takemitsu's music as Extreme Debussy! i.e if Debussy's music is stretched even further into atonality and add some Japanese instrumentation mixed in with the standard modern symphony orchestra, then you could perhaps imagine what Takemitsu's music sounds like, before you actully listen to it. But at the reasonable price that this set is sold, I would say if you are not sure, then it's not a huge expense to experiment with new and contemporary music at this price and see if you like it.