Google's (NASDAQ:GOOGL) biggest hardware partners are on the cusp of rolling out their next flagship smartphones. This spring should see the release of new, high-end Android handsets from Samsung (NASDAQOTH: SSNLF), Sony (NYSE:SONY), HTC, and LG, all of which will compete head to head with Apple's (NASDAQ:AAPL) iPhone.

Samsung should unveil the Galaxy S5 next week
Samsung's Galaxy S5 should be unveiled next week at the Mobile World Congress. Like Samsung's prior models, the Galaxy S3 and Galaxy S4, the device should be the most significant of Apple's competitors.

Various reports have indicated that Samsung's upcoming phone will sport, among other things, a fingerprint scanner, a super high-definition screen, a 16-megapixel camera, and a top-of-the-line processor. According to ZDNet, the phone might be waterproof and dustproof as well.

Samsung's gimmicky software features could be toned down in favor of a more pure version of Google's Android, and the screen size could get a slight bump, up to 5.2 inches from 5 inches on the Galaxy S4.

Sony's next flagship could also come next week
Alongside Samsung, Sony is also expected to unveil its next flagship, the Xperia Z2 at the Mobile World Congress. As with the Galaxy S5, Sony's flagship will reportedly sport a larger, ultra high-definition display, a faster processor, and more RAM. As Sony started the trend toward waterproof smartphones, the Xperia Z2 will likely be both waterproof and dustproof.

Sony's software could set its smartphones apart from its competitors. Sony's version of Google's Android includes a number of Sony-specific apps centered around its entertainment assets. Earlier this year, Sony announced PlayStation Now, a video game streaming service that promises to beam video games over the Internet to web-connected devices. Sony has promised to bring PlayStation Now to smartphones, and the Xperia Z2 could be the first of such phones to feature it when the service goes live this summer.

HTC goes for the gold
HTC last flagship, the HTC One, was well-reviewed, but it failed to sell as well as HTC had hoped. Despite coming in short of expectations, it doesn't look like HTC has many changes planned for its next handset.

On Wednesday, Twitter handle @evleaks posted an image of what appears to be HTC's next smartphone. Although HTC put a fingerprint scanner on its last phablet, the HTC One Max, it doesn't look like the HTC One 2 will sport that particular piece of biometric technology. It will, however, borrow something else from Apple's iPhone 5S -- a gold paint job.

Most interesting could be HTC's decision to include two rear cameras. The last major phone to sport two rear cameras -- the LG Optimus 3D -- was capable of recording 3D video.

LG continues to blur the line
LG's most recent flagship, the G2, couldn't record 3D video, but received largely favorable reviews from tech critics. Nevertheless, the handset didn't set any sales records. According to Digitimes, citing sources, LG sold just more than 2 million G2s last year -- far less than HTC and Samsung. Launching around the same time as Apple's iPhone 5S, the handset may have been overshadowed by Apple's product and its own Nexus 5, a cheaper variation of the phone sold under Google's brand.

With a 5.2-inch screen, the G2 straddled the line between smartphone and phablet. According to Pocket-lint, the G3 will take that a step further, with a 5.5-inch screen (the same size as Samsung's 2012 Galaxy Note II).

Like Apple's iPhone 5S and Samsung's upcoming Galaxy S5, the G3 is said to be equipped with a fingerprint scanner. The phone is expected to launch in May.

The smartphone is now a commodity
What should be apparent, reading through the descriptions of these upcoming phones, is just how similar they all are. Beyond just sporting Google's Android, they should all pack a high-definition screen between 5 and 5.5 inches, faster processors, and plenty of RAM. At least two of them should have a fingerprint scanner, and like Apple's iPhone 5S, one of them could come in gold.

At this point, it seems clear that the high-end smartphone market has been completely commoditized. Samsung has advantages over its rivals in terms of brand recognition and retail presence, but it's virtually impossible to tell these phones apart based on their spec sheets alone.

As with the PC market, Apple's advantage lies in its exclusive control of its operating system, which separates it from its competitors. Still, in terms of hardware features, high-end smartphones have become virtually indistinguishable.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.