I think in a bathroom granite is a better choice but I have stayed in a hotel in Rome with an all marble bathroom that was installed in 1947 and still looks awsome but pretty sure no one has dyed their hair in there which would be deadly with either of those choices. I think you need to figure out how you use the bathroom then get a counter that works for you. BTW I love Godmorgon from Ikea you can order without a top and then get whatever you want and the storage is amazing compared to most vanities.

Use of most household chemicals will mar the marble. Do you want to be able to set down a bottle of, say, toilet cleaner on your vanity without watching for any drips. Do any of the users of this bathroom use finger nail polish remover? Acne cream? Alcohol wipes? Do you ever have drips off your sink cleanser or overspray the sink while cleaning with scrubbing bubbles? It all depends on what you use in your bathroom and how much “patina” (fancy name for a marred surface) can you tolerate?