Which is the best coordinate system to perform the box cell minimization?

[mrshirts]

Right now, the minimization is done in the 6 box vectors of the crystal box. Would it be better (i.e. more numerically stable) to have the minimization variables be A,B,C, $\alpha$, $\beta$, $\gamma$? (one mapping is http://gisaxs.com/index.php/Unit_cell)? It is not immediately which is more stable.