I run 52, what they said about the reduced wear is true in my experience. You're probably already aware but you may have to worry about clearing the chainstays with bigger chainrings. You might need to factor in your bb spindel's length in terms of suitability.
I notice you're going fixie, but another benefit with 52 is that you're in a better place to work with most easily available SS freewheel sizes (such as shimano in 16, 17, 18t) if you decide to go SS freewheel at a more challenging gear ratio. With a 42T chainring, those common sizes would be too easy.