Not having owned the Flyye ones I can't say if this applies, but it has been observed that the Marine version is the preferred version out in the world. It's not as bulky and awkward. The Land version has more loops to carry more pouches but then that's even more bulk.
The Marine (as in water not USMC) is also supposed to be easier to get out of in a jam. That way if you fall in the water and are getting dragged down you can shed it faster. For land based folks that comes into play if you ever have to give someone first aid and need to get their gear off.
Airsoft, where nothing is hurt but feelings.