I still prefer the iPhone hardware/software combo.
BUT - if I had to switch to a Nexus 5 running Lollipop, I would hardly complain.
(And the price point is amazing...)
IMO, Lollipop is currently the best Smartphone OS for the average smartphone user...
For a professional review, checkout The Verge's review [Note: it blurs the line between Nexus 6 and Lollipop, but still - it's good] (http://www.theverge.com/2014/10/28/7082875/12-best-new-features-android-lollipop-nexus)
If you need a cheap and good phone/OS combo, go for the Nexus 5 and install Lollipop.
You _will_ be happy!