I would pick the EX over the LX. The EX is a solid binding that doesn't seem to have many mechanical problems (I haven't had any or heard of any). The LX is a low budget solution and judging from the reviews it shows. I would shell out the extra cash for the EX, they won't let you down.
^ I 100% agree. My buddies who work at shops only stock a few LXs and hardly push'em.