Montgomery was a coward, he wasn't willing to take risk if it ruined his reputation.
Not his reputation, his army. He cared too get the job done, thats all. Allways fighting the main German force while head on wasnt the best way to get fameous but it had too be done by someone.
Patton on the other hand didnt care about getting else than reputation. His father once said to him: "George, I got the money for the family, you get the glory". Thats why solidiers called him "His guts, our blood".
IMO Omar Bradley was the best US general.