Perhaps Red Giant is more ubiquitous than Singular Software and thus should have better distribution and maybe package deals that can push the price down on Plural Eyes. Meanwhile, this could be incentive for Apple to further develop FCPX’s syncing protocols because it is easily stymied by multiple video and audio clips.
For example, all my recent music shooting with two cameras and constant Zoom audio placed clips all over the wrong places on the FCPX timeline after “syncing.” I ended up syncing manually. Fortunately beforehand I assured the cameras and Zoom all had the same time-of-day clocked, and that helped immensely, in fact it was fairly simple. All that to save $149 from buying Plural Eyes. Well, I guess I’m a cheapskate. If PE could sync a lot of data accurately it’s probably worth it.