This boxed set contains numerous widely-praised DG recordings and represents unmatched value for money. For example, the magnificently played Brahms symphonies are also available separately, but you would pay a significant percentage of the price of this large box (about 50%, when I bought it). So even if you have some of the recordings already, this box can still be the way to go if you want to add to your Abbado symphonies collection. And if you do not have any of these recordings already, but wish to acquire some or all of them, the term "no-brainer" could have been invented for the purchase decision.
Generally, I will try to balance reviews by pointing out any downsides of a product. There are none in this case. Buy with confidence.