They have more in common than you might think when looking at the ending and how that turned out. Other than both being firemen, they have both read books, and had that curiosity about books. Beatty even admits this to Montag; he states that he himself was once like Montag, who "read a few lines and off you go over the cliff. Bang, you're ready to blow up the world...I know, I've been through it all." So he's read some books and felt that change of heart that Montag is experiencing, and that desire to change the awfulness that exists in the world. Montag feels that desire also, and it leads him into disillusionment and rebellion, and to eventually completely turn against his entire world and life. Beatty however, seems to have delved into books and then formed the bitter opinion that "What traitors books can be! You think they're backing you up, and they turn on you." He thinks that they end up just being words that anyone can use to their purpose. Knowledge is useless because it doesn't do anything-it's just words people throw at each other. So, he goes back to burning books, possibly with more vengeance than before.
Montag and Beatty are both men of strong passions, more educated than the average person in their society, and familiar with a different choice for society. However, Montag embraces that choice, and Beatty rejects it.
Although Montag and Beatty are quite alike and different in ways, Bradbury had another character to be compared to Beatty; Granger. Just like a lot of other things in the book, the two characters are almost polar opposites; Beatty is the fire chief and hence is destroying all knowledge while Granger, leader of the "hobo knowledge seekers" presrves the knowledge. Granger doesn't follow the rule while Beatty is an extreme stickler for them