My local GC has had a Vertex in stock since they were released. I have played it once and was not at all impressed. I've owned both a Flea 4 and 5 so I was expecting something similar. The neck is wonderful but everything else seems uninspiring.
The bass is passive and the single pickup is positioned in between where a P and MM would be. So you'd sort of expect it to sound not quite like a P and not quite like a passive Ray. The bass just seemed unresponsive, nothing lively or exciting. I'd like to say it was just the strings, but it was something more than that. Maybe it sounds great in a mix, but I'll probably never know.
Additionally, the body is oddly shaped and balanced. Maybe it works better on a strap. I don't know. There was absolutely nothing inspiring about my experience with one. It's isn't a bad bass, but for the price, I guess I just expect a lot more.
IMO, IME, and YMMV, of course.