There is little comparison. Better to compare the Neurosky products to emotiv's, as both have been on the market for several years.
Here's a comparison chart that covers consumer BCI devices. It stands to reason that multi sensor devices are capable of more functionality than single sensor ones like the Mind Wave and Neurosync.
You answered your own question. The Neurosync is targeting the wearable market and Emotiv targets the Star Trek group. Last year CNBC tested the Emotiv headset and felt that it was interesting but with limited appeal because of how it looks. They felt that the key opportunity is in wearable's market especially for the millennials.Thus the worlds smallest BCI device.