The Verge has a pretty well written, even handed review of the Nexus 5:
http://www.theverge.com/2013/11/4/50...nexus-5-review
Sounds like it's a lot like the Nexus 4 when it was released; some good software updates, beautiful screen, very fast and responsive, but with a disappointing camera and questionable battery life (they describe it as "somewhere between bad and okay."). It also sounds like Hangouts has done a pretty poor job of integrating text messaging.