Here's how the three devices stack up.
Users who simply want the largest screen possible should go with the Galaxy S5. The Samsung device features a 5.1-inch, full 1080p HD screen. In second place is the HTC One (M8), which features a slightly smaller, 5-inch 1080p HD screen.
The iPhone 5s is much smaller than its rivals, with just a 4-inch high-resolution Retina screen.
Price and availability
For now, getting the iPhone 5s is much easier than getting the GS5 or the One (M8). The Apple device came out last September, so it's available widely. A 16-gigabyte version of the gadget normally retails for $199.99, with a two-year contract but it's not hard to find an iPhone 5s for less than that -- Best Buy and Wal-Mart often have it on discount.
The HTC One (M8) is on sale online through AT&T, Sprint, Verizon and Best Buy, but until April 9, only Verizon will sell the device in stores. T-Mobile will begin selling the Taiwanese phone in stores and online on April 11. A One (M8) with 32 gigabytes of storage normally retails for $199.99, but most carriers offer monthly payment plans as well.
Customers can preorder the GS5 from AT&T, Sprint and T-Mobile, but it won't arrive until April. Verizon is also set to carry the device but has not when it will begin selling it. The GS5 comes with 16 GB of storage and normally retails for $199.99 with a two-year contract but can also be purchased with monthly payment plans.
Users who want the slimmest phone will want to get the iPhone 5s, which is 0.3-inches thick. That's followed by the 0.32-inch thick GS5 and the 0.37-inch thick HTC One (M8).
The iPhone 5s is also the lightest of the three, weighing 0.25 pounds. Meanwhile, the GS5 weighs 0.32 pounds and the HTC One (M8) comes in at 0.35 pounds.
The HTC One (M8) has a very unique situation when it comes to its camera. The device actually sports three: one on the front and two on its back, including the main lens which captures images with HTC's UltraPixel technology.
The two cameras on the back, meanwhile, work together to let users capture depth in their photos. HTC also claims that the Duo Camera, as the pair of back cameras is formally called, also makes it possible for users to refocus their photos after they have already been shot.
In terms of megapixels, the GS5 is the winner. It sports a 16-megapixel rear camera. Samsung also boasts about the camera's ability to quickly focus on its subjects
On paper, the iPhone 5s features the least exciting rear camera, offering just eight megapixels. When it was announced, Apple marketed the camera's ability to quickly shoot multiple photos and shoot video in slow motion, but those features are also available on the GS5 and HTC One (M8).
The HTC One (M8) is powered by a 2.3-gigahertz quad-core Qualcomm Snapdragon 801 processor while the GS5 has a slightly more powerful 2.5-gigahertz quad-core Qualcomm Snapdragon 801 processor.