From an optical standpoint, the Cross Spike Version introduces minimal obstruction and can deliver slightly sharper images. If you do not like diffraction spikes, or if you need to rotate the CAA very often, the Spike-Free Version is the better choice. However, unlike a refractor, residual diffraction artifacts may still be visible in bright stars due to factors such as stress in the Schmidt corrector plate, although the results are significantly cleaner than with traditional solutions.