The Artifact armor you get at 45/50 isn't the best. There's a second 'set' of Artifact gear at 50 you can buy for Mythology tomestones but that's not what your referring too. But yea either Darklight (From Philosohpy Tomestones) or the Vanya (Crafted) would both be a good upgrade from the base class armor you start with. It all comes down to what you like better.