The Nex is hugely customizable. I had a Nex 5 for a while. In its default form, it was a PIA, to be sure. But once FW 3 came out (and I believe its a couple of versions beyond that now), you could easily set it up so that all of your important adjustments were either immediately available or no more than one click away. Based on my experience with the GRD3, I'd say the Ricoh is the top of the pile for UI and ergonomics, but the Nex, X100, and the m43 cameras I've owned and used are only slightly worse and mostly in theory. I can always make an argument for why the Ricoh is better, but in use, the differences melt away and all of these cameras are easy to set up so your key adjustments become second nature VERY quickly. I like Pany the least of them because you always have to click the main control dial to change functions and its easy enough to lose track of which function its controlling, but this is a minor annoyance at worst and I've used them happily in the past. Its tough to find a badly designed camera these days.
-Ray