It was something of a miracle that I even found Chow's textbook. My Econometric's professor said we could use any textbook we'd like, then gave us a list of ten recommended books (non of which were Chow's). I went to the library to see which book suited me best, accidentally pulled Chow's off the shelf, and thought it was great.
He writes concisely--the way math students like to learn from. As a math major, I found it delightful to only have to read a few dense pages to understand a topic. Whereas with Greene, you get examples and explanations, Chow will often just lay out a few definitions, some theorems and proofs, and leave it to the reader to develop their own intuition. For those who like to learn that way, it's great. For those who don't, it can be a nightmare.