Personally I think it's a mistake to only think 'which axanthic is better'? These are different non-compatible mutations that produce a similar look through different means. Each one is going to affect the looks of a combination morph in different ways. So far the only axanthic clown is made with a tsk axanthic, the only true ghost is made with a tsk axanthic and one of the whitest of the snowballs is made with a tsk axanthic. VPI and TSK axanthics may produce somewhat similar colors as babies, but in reality they're two different pigments on the ball python palette. Why not have both? The more base morphs you have access to, the more combination possibilities are open to you.