We're yet to publish a full review of the HTC One, but having seen the flagship HTC in person we can safely say it is one of the best smartphones ever made.
To our eyes the One is a very handsome phone, with just enough exposed aluminium without looking industrial and not too much plastic so as to feel cheap - we're big fans of HTC's flagship and expected a lot from Samsung to counter it with the S4.
On the face of it, the One and Galaxy S4 are both similar devices, but they couldn't be coming from more different origins if they tried.
Samsung is Goliath here, with its enormous marketing budget, worldwide consumer appeal and strong history of being the company to take on Apple. HTC, once a worthy contender, has become David, with declining sales, a small product range and marketing budget that seems to have been entirely drained on Champions League football advertising.
Samsung had two options with the S4; it could reinvent its flagship entirely as it did with the S3, which was a huge update to the S2; or it could take the Apple route of a few minor updates, resting on its laurels.
HTC, on the other hand, has gone for bust with the One, and it needed to. Put short, it has created one of the best smartphones I've ever seen - it's design and construction is on par with the iPhone 5, it's really that good.
On first inspection, Samsung has done little to rock the boat with the S4, instead opting for a very similar design to the S3, although with slightly squarer corners and a screen 0.2in larger. Evolution, not revolution.
Both phones have a full HD screen resolution of 1080 x 1920, although due to its slightly smaller size (4.7in vs 5in), the One has a higher pixel density of 469 pixels per inch, compared to the Galaxy S4's 441ppi.
Above their screens both smartphones have a 2.1-megapixel camera capable of 1080p HD video recording, and the Galaxy S4 uses its camera to monitor eye movement. Read down the screen and the phone will automatically scroll up, or look away while watching video and it will be paused until you look back at the screen.
Powered by an Exynos 5 Octa chip, the Galaxy S4 is technically a quad-core smartphone with eight cores at its disposal. Dubbed big.LITTLE, the phone can make use of a 1.8GHz quad-core processor for heavy work like 3D gaming and HD video, but can also rely on a 1.2GHz quad-core processor for less intensive tasks, like text messaging and Twitter. This way, the Galaxy S4 can save on battery life while still having huge power when it's needed.
Although the HTC One misses out on the clever big.LITTLE technology, it's still a hugely capable smartphone with a 1.7GHz quad-core Snapdragon processor by Qualcomm; both phones have 2GB of RAM.
Both the HTC One and Samsung Galaxy S4 use Android 4.2 Jelly Bean and both cover it with their own skin, Sense 5.0 and TouchWiz respectively.
The biggest feature of HTC's Sense system on the One is BlinkFeed, a Home screen widget that aggregates news from across the web and your social networks, displaying it in a way similar to Flipboard.
Samsung has included its 'designed for humans, inspired by nature' user interface with the S4, so annoying beeps and bloops every time you press the screen is the order of the day. Thankfully, this can be turned off, leaving an attractive and easy-to-use operating system.
Anyone who has used a Galaxy product in the last year or so will feel right at home with the S4.
For consumers wanting Android as Google intended it, the LG Nexus 4 is one of the very best smartphones on sale, and at £239 it is considerably cheaper than any of its rivals.
Opting against a war of megapixels to find who can offer the most, HTC has taken an alternative route with the One, offering larger pixels instead of more.
Recognising that eight- or 13-megapixel photos are huge, take up space, are slow to email, and will be scaled down when shared on Facebook and Twitter, HTC has instead created a camera that is just 4-megapixel, but lets in much more light - and therefore detail - than other cameras.
Early reviews have proved inconclusive, but with an HTC One being reviewed in our office right now, we will be able to determine soon if HTC is on to a winner.
Samsung has plucked for the simpler option of packing in more pixels with the S4, which gets a 13-megapixel sensor and LED flash. Finally, both phones record full 1080p HD video while shooting photos simultaneously.
The Galaxy S4 and HTC One are coming to the same fight from two very different corners, but so far we'd say the One wins in terms of hardware and design, while the Samsung looks to offer more performance. All will be revealed when we get our hands on the S4 and give it a thorough review and comparison with its rivals.