You never hear about Persian sources because they no longer exist. Virtually nothing survives from the Achaemenid written corpus, due in part to the destruction of major collection sites like Susa and Persepolis. We have the royal inscriptions, especially of Darius I and Xerxes (which are mostly in the Louvre, now), but that is all.

This comment bu /u/Daeres implies a more nuanced view, regarding our view of the Persian Empire.

We actually have a fair number of sources on Greeks from the Near East. Ionians and Carians settled in Egypt before the Persian conquest and their traders had to pay taxes. Neo-Assyrian sources complain about Ionian pirates and raiders, but may also employ Ionians as soldiers. Carians (deported from Egypt?) received rations in Babylonia. The Achaemenid Royal Inscriptions boast about bringing Ionians to practice their special skills at the palaces of Susa, and Greek stonemasons were brought to work at Persepolis and left a few short notes in Greek. And seals from western Anatolia show Persian heroes killing Ionians. These sources have been found, translated, and organized in the last hundred-odd years, and books like Amélie Kuhrt's =The Persian Empire= as well as academic articles by people like Bradley J. Parker and Robert Rollinger discuss them.

One reason that these sources are not better known is that they don't fit in very well with many of the stories we like to tell about the early Greeks. They portray Ionians as exotic foreigners with useful skills, like stone carving and fighting, strange customs like walking around naked, and threatening violence which needed to be crushed by the king, but really just as just another people from distant lands, not as overwhelmingly important or exciting. They don't have colourful anecdotes about individuals, just faceless groups of workers, traders, and raiders. Some Greek technologies and practices were attractive in the Near East, just like many Greeks were fascinated with eastern kingdoms and Egyptian wisdom, but we don't see much of that in contemporary writings from the Near East.