The iPhone 5s on the other hand has had more than a month’s head start on the shelves, waiting for its arch nemesis to roll up and face it in person.
Now that we've put both handsets through their paces in the Stuff reviews arena, it's time to throw them into the ring to see which one emerges victorious.
Metal vs Plastic
LG has played it safe with the Nexus 5, ditching the glittery glass rear of last year’s Nexus 4 for a polycarbonate shell which is heavily based on the 2013 Google Nexus 7 model - right down to the over-sized rear camera disc and vertically stamped Nexus branding.
In sharp contrast to the slippery plastic of the Samsung Galaxy S4, the Nexus 5 has a matte, soft-touch finish which offers a decent amount of grip (although if you're choosing colours, be aware that the white N5 is a little smoother).
The Nexus 5’s volume and power buttons are made from ceramic too – a nice touch which adds to its overall feeling of solidity and we're fans of its unblemished, clean front which shows off nothing but screen. According to Stuff reviewer Sophie Charara, "Google has finally discovered cool".
Having said that, there's no getting around metal. The iPhone 5s will feel like a more premium device in your hands, thanks to its aluminium build, and its new crystal sapphire Touch ID Home button, encircled by stainless steel, oozes quality.
If you’re not tired of the iPhone 5s’ design, then its metal construction pips the Nexus 5 to the build quality post.
Winner: iPhone 5s
The Nexus 5 boasts a 4.95in full HD display, with a 1920 x 1080 resolution. And despite it being an inch bigger than the iPhone 5s' 1136 x 640 screen, its higher resolution means it's a little more pixel-packed, with 445ppi compared to the iPhone 5s' 326ppi.
Its screen has a slightly cooler colour palette than the LG G2 and HTC One and viewing angles could be a bit better, but overall it's up there with the best full HD screens our eyes have ogled this year.
You can see the screen size difference between the Nexus 5 and iPhone 5s roughly demonstrated in the photo above, which shows off the 5.2in LG G2 (which the Nexus 5 is based on) next to the 4in iPhone 5s.
You won't really notice the difference between pixel density on both devices unless you go nose-to-screen, but for having a larger, higher-res display, we're giving this round to the Nexus 5.
Bump the screen size up Apple, and next year's round might swing the other way.
Winner: Nexus 5
Apple makes huge claims for the iPhone 5s' new 64-bit A7, and its pride in the new silicon is entirely justified (even though the consensus that its 64-bit processor won't serve any truly useful benefits - besides Touch ID fingerprint encoding - for the time being).
According to Anantech's in-depth benchmark tests, the iPhone 5s' A7 processor bests the Nexus 5's Snapdragon 800 processor across the board, demonstrating the raw power available for pushing pixels, gaming and running apps.
It's also worth remembering that the A7 processor is designed and optimised to work with Apple's own strictly controlled hardware, letting it squeeze out every last drop of efficiency and power available to it, and it shows. The iPhone 5s runs iOS 7 without a judder or hiccup in sight.
Numbers aren't everything however, and the Nexus 5 more than proves it by treating us to the fastest, smoothest, slickest Android experience we've ever seen, ploughing through the latest 3D games and multitasking apps like an eight-handed juggler.
Yes the Nexus 5 has 2GB of RAM in comparison to the iPhone 5s' 1GB. Yes the iPhone 5s' A7 processor has bigger, scarier looking numbers.
But and the end of the day, we've never seen iOS or Android run smoother than on these two smartphones.
Screw the numbers game. This one's a straight up draw.
More after the break...
While Android flagships like the LG G2 and Galaxy Note 3 are rocking 13MP cameras, the iPhone 5s sticks to its guns with an 8MP snapper. And it proves that megapixels are just a number.
The iPhone 5s takes detailed, bright, punchy snaps with realistic colours, and its dual two-tone LED flash adjusts colour temperature in real time, producing more natural skin tones. The result is a smartphone camera which produces some of the best shots around.
The Nexus 5's 8MP camera boasts optical image stabilisation, which has proven itself in both the Nokia Lumia 1020 and LG G2 by producing clear shots with sharp details, even in low light conditions, and it's a feature that's lacking from its iPhone 5s rival.
But sadly, the Nexus 5's camera gets a "room for improvement" stamp on its report card. Shots have muted colours and we found that we had problems with exposing shots correctly. They're not terrible, but we were hoping for better, especially as the G2's camera built up our expectations
Google has stated that software tweaks are on the way to help improve the Nexus 5's camera performance, but for now the iPhone 5s easily wins this round.
Winner: iPhone 5s
In tech years, Android vs iOS is a tale as old as time.
Google's recently revealed Android KitKat 4.4 has had a few welcome nips and tucks, in more ways than one.
Apart from looking cleaner thanks to transparent status and home button bars, KitKat brings deeper Google Now integration and more intelligent voice search to the table, along with NFC mobile payments.
Google Now is just one swipe on the home screen away from providing intelligent search and relevant location-based information (including website suggestions), which coupled with the improved voice search turns the Nexus 5 into a brainy pocketable butler.
And of course, you can customise Android's appearance any way you see fit. No Jailbreaking required.
iOS 7 on the other hand offers a better curated App Store, Apple's ecosystem (which many people have heavily invested in) and, of course, the iPhone 5s' home button which can scan up to five fingerprints to unlock the device as well as pay for apps without entering annoying passwords every 10 minutes.
Ultimately though, Android 4.4 KitKat is so clever it manages to slide ahead of iOS 7. So much so in fact, that we crowned it the best smartphone OS in the world, which is why the Nexus 5 comes out on top in this scrap.
Winner: Nexus 5
Both the iPhone 5s and Nexus 5 are top-notch devices with plenty going for them. The iPhone 5s' faster benchmark performance, longer talk time and premium metal build make it a winner on paper, but it can't compete with the Nexus 5's larger, more pixel-packed screen and super-intelligent Android 4.4 KitKat smarts.
Factor in the iPhone 5s' £550 price tag in comparison to the Nexus 5's superb £300 asking price, and it's a no brainer. Unless of course you're a devoted Apple/iOS fan, in which case your decision has already been made.
The Nexus 5 is almost the perfect Android device and can be yours for a price that's too tempting to pass up.
A worthy winner then, and an important W on Google's scoresheet, which is why it slots in above the iPhone 5s in third place on Stuff's Top 10 smartphone list.