There are so many devices based on Google’s Android operating system that it’s hard to keep track of them all. But each year Google works with a hardware maker to produce a “best of Android” phone and tablet, called the Nexus models, which are often used to launch a new version of the OS and to strip away the quirks and variations other makers and carriers layer on top of Android.

I’ve been testing the latest of these Google-designed phones, the Nexus 5 made by LG of South Korea, and the newest version of Android, called KitKat, or Android 4.4. I like both, though neither is an especially bold leap forward in features. They are mainly designed to do two things: to integrate Google’s own features and services even more deeply into Android, and to lower the price of phones capable of running the latest version of Android.

The Nexus…