Hi, Geoff. First off, welcome to the forum. To answer your question, I would say the benefits of the NEX are many, but it will depend on what you are looking for in a camera. In comparison to the X100, the NEX gives you interchangeable lenses. With m4/3, in my opinion, it is a much better sensor with improved high ISO capability, better dynamic range, and a larger sensor. With Samsung's NX system I would say Sony still has the better sensor even they both are APS-C sensors. Now, Ricoh's GXR is an interesting alternative but I like interchangeable lens better than their lensors, although their new M-mount module is certainly compelling.
To balance the discussion, Samsung's NX and the m4/3 system have a much better range of native lenses and the X100 seems to be the kind of camera that, if it meets your needs, seems to make its users fall in love with it. It has a certain unique charm.
I chose the NEX for its amazing sensor, focus peeking, and the fact that my legacy lenses benefited from the 1.5x crop factor. Its small size and flip-up rear LCD were nice bonuses. I've been happy with my choice and would recommend a NEX.