The first one looks higher quality (to me).
Go by what fits you and your horse best. (I know that can be really hard to know if you are buying over the internet). Picking a saddle by what looks best is like buying a horse based only on it's color!
Also, consider what features you might like best. For instance, round skirts vs. square. Regular swells vs. the swept back bear-trap swells on the second one. The first saddle might have more of a rise to the seat, the 2nd one looks fairly flat, etc.
Are there any indications on which tree might fit your horse better?