Get the bank or broker to run it both ways and check the best scenario. We ended up going with just my husband on the mortgage (as an immigrant, my credit history is shorter and dragged our interest rate up 0.25%) but we are both on the title of the house.
However, by the time we bought a second place, my our credit scores are in the same range, though still 50 points apart, and we got the same rate regardless of which of us took the mortgage, so we are joint on that.