I have only seen two Nexus 4 and one Nexus 5 outside of mine. Most people have never heard of Nexus and most people don't even know Google sells any phones or tablets.
I suspect that is changing.... I remember a year or two back, people remarked at how few times the presenters at I/O said "Android"..... and wondered if they were de-emphasizing the Android brand and pushing more "Google".
My, how things change... .at this year's conf... Android was ALLLLLL over the place. You couldn't shake a smartwatch without seeing the Android logo or hear a presenter say the word. We see reports that Android will not allow companies to screw around with their new platforms (I'm looking at your Samsung).... What we hear of Android Silver is basically a high-end brand of phones with Nexus-like software... then, music to our ears, someone at Google saying, out loud, that the Nexus line isn't going anywhere. Google is looking to reassert themselves and take their mobile OS back a little.
With the Nexus 5, I've seen it described as the best smartphone no one knew about.... Google didn't really push it... we SEE it everywhere (in all those screenshot mock ups, etc) but they don't give it the full court press that we see when Samsung releases a new Galaxy S.... we don't even get a smug, pretentious ad with Gary Oldman in it. I think we'll see a big change with the upcoming phone.
I think the Nexus 6, or whatever they call it, will be a BIG event... Google will roll out a new Nexus phone AND tablet, a new OS... and I bet you that they also officially launch the Silver line, with the Nexus as kind of it's torch bearer. By this time next year, when you tell someone you have a Nexus, you won't get an odd look.... watch.