There is not that much to add to the other reviewer's comments: these two discs are a bargain and unreservedly recommended. Ashkenazy is indeed the very best overall Chopin interpreter around. I immensely enjoyed his treatment of pieces such as the second scherzo and the g minor ballade. Not to mention the etudes, the preludes, etc. etc. All is crisp and clear, and the fact that some recordings are analogue doesn't matter at all: in fact, they are hard to be discovered.
But keep something in mind: as I said, Ashkenazy is arguably overall the best. This implies that he can be bettered in some ways. Philips has also released a Best-of Chopin set, which contains better renditions of some Waltzes (Kocsis), the Barcarolle and Mazurkas (Kovacevich) and the impromptus (Davidovich). Additionally, the Philips discs give you the Marcia funebre, the Fantaisie-Polonaise and the fourth Ballade, three big pieces that cannot be found over here. Overall it is more balanced too. So if you are going to buy just one best-of-Chopin set, go for the Philips. The best choice, however, is to get both of them!