Android cell phones seem to have a lot of security problems. At Google I/O 2016, Android developers cited security issues on the operating system as being the largest problem the team is having to deal with. It’s gotten so bad that one top security research recommends Android users only buy Nexus or Samsung devices. Because of this, researchers are saying that they can’t really advise buying any other brands from a security standpoint.
You can read more at http://www.androidauthority.com/only-nexus-samsung-secure-701287/ as well as by followng links that are in that article.
I must say that I love my Nexus 6P that I purchased about six months ago.