I loved this phone a lot, even after using for last two years, I am not facing any kind of lag and it is still one of the fastest cell phone in the market.
Nexus itself is a brand name and it has let upto it's name and expectations, even after 2.5 years of its release Google nexus 5 still offers the latest Android os, that is Android 6.0.1 marshmallow, it even get security update every month.