During a stay on Crete in the summer of 2018 I visited two of the properties of this serial site. One of them, Knossos Palace is the most visited tourist attraction on all of Crete.
Although British archaeologist Arthur Evans, who excavated Knossos in the early 20th century, firmly placed the palace as the residence of the mythical King Minos (and named the whole civilization after him), you will not find any remains of the Minotaur’s Labyrinth here. Instead, among the ruins of stone walls and buildings, you will find partial recreations of structures as they existed thousands of years ago. While the relatively young age of these recreations is obvious to the naked eye, they are considered very faithful facsimiles. There are a couple of interior spaces among the recreations as well as a few paintings – none of which are originals, of course – which enliven the scene a lot.
All of that makes Knossos almost “livable”, especially compared to a site such as Phaistos (sometimes transliterated into Latin alphabet as Faistos). The two are contemporaries, although Phaistos Palace came to ruin and disuse a few centuries earlier than Knossos, around 1450 B.C. There are no reproductions at Phaistos, only whatever has been excavated in the shape that it was found. An expert in archaeology may actually find that more authentic and rewarding. For a layman visitor, an uncommon power of imagination is required to discern anything more than terraces of piles of rocks, no matter how much explanatory details are provided in the accompanying materials. Occasional obvious artifacts do pop up, and the surrounding valley views are spectacular.
Unless you are a devoted student of archaeology, I suspect that you will find Phaistos boring. Knossos, on the other hand, is well worth the visit. It probably pulls my overall mark for the property to 3 stars.
Knossos is just a few minutes away from Heraklion by car, while Phaistos is a bit over an hour away.