I'm just starting to teach myself about covariant and contravariant vectors. With the little knowledge I've acquired so far I'm wondering if, for an ordinary Cartesian vector $\mathbf{V}$, it's OK to write $\mathbf{V}=V^{x}\hat{e}_{x}+V^{y}\hat{e}_{y}+V^{z}\hat{e}_{z}$ or is the correct notation $\mathbf{V}=V_{x}\hat{e}_{x}+V_{y}\hat{e}_{y}+V_{z}\hat{e}_{z}$
with subscripts, which seems to be they way they are written in my textbooks? Does it matter? I understand there's no difference between Cartesian covariant and contravariant vectors. I'm just curious why subscripted components tend to be used. The first version does sort of look “more balanced”, but what's the official line on this?
Thank you