I have both sets.
Each has its advantages. Warlords are more dynamic, particularly when put together in massed units. In the minus side, the figures are somewhat rougher. In a box you get 4 basic poses.
Victrix are better sculpts, with better detail, but the figures are just in one pose, standing. I like more the faces and helmets from Victrix, as well as the pikes, which are more accurate than Warlords. Victrix Successors sets include alternative legs, with trousers, to represent Persian recruited phalangites.
Victrix figures are slightly bigger than Warlords. It is scarcely noticeable from typical "wargaming distance", though.
To be honest, I have found Victrix easier to paint -better detail-. If they would have released advancing/attacking sets I wouldn't bother with Warlords. Alas, they haven't, so Warlords it is, for some variety.