For the last couple of years, Google has reserved the “Nexus” label for smartphones that provide the purest experience of its Android operating system. Meanwhile, Samsung has used the “Galaxy” brand on its top-of-the-line mobile devices.

So what do you get when you marry the two and put the result on the best 4G network? The Galaxy Nexus, a superphone that is still somehow a little less than the sum of its considerable parts.

The Galaxy Nexus, which costs $299 on a two-year contract from Verizon Wireless, is the first device to ship with Android 4.0, or in Google’s dessert-based nomenclature, “Ice Cream Sandwich.” It is supposed to blend the separate cell-phone (“Froyo,” “Gingerbread”) and tablet (“Honeycomb”) flavors of Android’s operating systems.

The idea is to simplify things both for developers, who otherwise have to worry that apps written for one version of Android won’t run on another, and for consumers, giving them a similar experience no matter what kind of device they’re using. Apple, not surprisingly, set the bar here with one operating system — iOS — running iPads, iPhones and iPod Touches.

Lard-Free

The Nexus phone is mercifully free from the proprietary user interfaces and apps that manufacturers and carriers often lard atop Android. And Ice Cream Sandwich brings some welcome enhancements.

Physical buttons are out. In their place are on-screen back, home and recent-apps controls that rotate along with the display when you turn the phone into portrait mode. You can also create folders of apps by stacking them one atop the other, and — as on Honeycomb tablets — summon thumbnail images of open apps with the recent button. If you see one you don’t need, a sideways finger flick dismisses it.

One major innovation isn’t so successful: Face Unlock, which theoretically allows you to unlock your phone simply by holding it up to your face and letting it recognize you. It’s a neat trick when it works, but I repeatedly got error messages telling me I couldn’t be recognized. Take it from me: Few things in technology are as depressing as being rejected by your own phone.

Some users, meanwhile, have reported being able to fool the feature by holding up a photo of themselves; even Google warns during the set-up process that Face Unlock is less secure than other ways of protecting your phone.

As for the Galaxy Nexus hardware, it’s handsome without being particularly distinctive. The nicest feature is the big 4.65-inch screen that, typically for Samsung devices, is absolutely gorgeous, with deep blacks and ultra-rich colors. My main complaint was the automatic-brightness level, which is supposed to adjust to ambient light but that I found consistently too dim for my tastes. Eventually, I went into the settings and disabled it.

Under the hood is a dual-core Texas Instruments processor, plus a gigabyte of memory and 32 gigs of storage. There are also 1.3-megapixel front and 5-megapixel rear-facing cameras, and it shoots video in full 1080p high-definition. The whole package is still only a third of an inch thick and weighs about 4.8 ounces.

Power Outage

In the United States, the Galaxy Nexus runs on Verizon’s LTE 4G network. LTE is the fastest network technology, and Verizon has the broadest coverage. But there’s a catch: LTE also gobbles battery life. I’ve generally found that Samsung does the best job among LTE handset-makers in managing power. But I’d be tempted to take advantage of the fact that — unlike iPhones — the Galaxy Nexus’s battery is user-replaceable, and carry a spare.

A version of the phone is also in the works for Sprint, which will start rolling out LTE this year. A model with 16 gigabytes of storage and using HSPA+ — yet another network technology — is available in other nations where LTE isn’t widespread. Carriers offering this version of the phone include Vodafone and Telefonica’s O2.

Because of Google’s open-to-all-manufacturers approach, it’s hard for any Android phone to match the seamlessness of an iPhone, Research In Motion’s BlackBerry or even devices running Microsoft’s Windows Phone 7. Perhaps that will change after Google takes control of handset-maker Motorola Mobility Holdings. Until then, the Galaxy Nexus comes closer than anything yet to providing the definitive Android experience.