I've had better luck with Garvey and, since I like a good defensive club, I love the 1 fielding rating.
The one problem with Garvey is that he's right-handed. Since there's a paucity of decent lefty third-basemen in 70's (and lefty catchers, and lefty middle infielders), I really like to have a lefty at first. Otherwise, my teams get too righty-heavy.
But Murray tends to under-perform for me, while Garvey is solid. Go figure.