What are the pros/cons of the SM81 vs AT4040 specifically for voice?

The targer vocalists are young female and male rockers, older male blues and rock.

hi friends1
I am a big fan of AT mic line. In fact I have three on here, workin fine since 1996, used for orchestras, horn bands, in almost every day job recording section.
I want to buy another mic. what are the differences between at4050 at cardioid and the new :p model at4040 that only does cardioid?
will they function as a couple?
thanks