They are both 18650 cells in a 14x6 matrix for 84 cells. The cells are the same capacity, 3500 mah in both cases. Luna tells you that they use LG MJ1 cells, while the other guy offers Panasonic 35E or Samsung GA.

Of these three types, I would rank the GA and MJ1 first, as they are rated for 10A discharge, while the 35E's are rated at 8A. With 6P, theoretical max currents would be 60A for the first two, and 48A for the 35E. In practice, your controller determines what you will pull, but the MJ1 and GA will have an easier life and last longer if you don't get close to their max ratings,

Anyway, you cannot get a Luna pack,