Which is stronger – a whale or a cat?

much depends on the map; on almost all XL+U maps, except perhaps 8x8, I would choose the Titan. On most other maps, taking control of Confluxes and Hives is easier and more convenient with the Archmage (the Titan cannot move and attack simultaneously if there isn't a creature blocking it, and this is its main disadvantage), and that says a lot.