Look familiar? Sizes are very similar, with the biggest difference being the GS4's eight percent thinner frame.
Another encouraging sign for the Nexus 5, as it's the same light weight as the Galaxy S4.
Both phones are plastic, but the Nexus 5 has a matte build (similar to the 2013 Nexus 7), which should feel different from the glossy plastic GS4.
Resolutions are identical, and screen sizes are roughly the same. The Nexus 5 has an IPS display, which should have more toned-down, realistic colors than the hyper-saturated AMOLED screen in the Galaxy S4.
Both phones are very fast, but the Nexus 5 has the advantage with its Snapdragon 800 processor.
Note that the CPU listed above is for the LTE version of the Galaxy S4. The HSPA model, available in some countries, has an octa core Samsung Exynos processor, clocked at 1.9 GHz.
Both phones also have 2 GB of RAM.
The Galaxy S4 gives you more storage options, as well as microSD card support.
This might be the most notable upgrade from last year's Nexus 4. It technically had LTE capabilities, but its software disabled it. The Nexus 5 gives you LTE by default, making it a much better buy in markets that offer the speedy cellular data network.
The GS4 holds a bit more juice, but we'll have to wait a while for some Nexus 5 battery tests.
The GS4 wins on megapixels, but as you may know, that doesn't necessarily translate to better pictures. That's another front we'll have to stay tuned on. One bonus that the Nexus 5's camera gives you is optical image stabilization, which should help to cut down on the effects of camera shake.
No IR blaster in the Nexus 5, so only the GS4 will let you change channels on your TV.
Pretty much a standard on modern high-end Android phones, both phones have NFC chips.
Carriers are just beginning to roll out their Android 4.3 updates for the Galaxy S4, so the Nexus 5 will launch two full versions ahead of many GS4s. It runs the brand new Android 4.4 KitKat, with its redesigned launcher (home screen), voice activated ("OK Google") search from that home screen, improved phone app, and much more.
We could write a book on the GS4's software, thanks to Samsung's kitchen sink feature strategy. Feel free to hit up our comparison of the GS4 to the HTC One for more on the Galaxy S4's TouchWiz features.
We aren't quite in the "bad time to buy" zone for the Galaxy S4, but if next year's release cycle is the same, then we're probably about halfway towards the Galaxy S5. The Nexus 5, of course, just hit Google Play today.
Speaking of Google Play, that's the best place to buy the Nexus 5 ... or at least it is if you can get your hands on one. Minutes after going on sale, shipments were delayed to a week. As of the time of this writing, the 16 GB version is completely sold out, and the 32 GB model ships in three to four weeks.
But if you can snag one from Google Play, you can get quite a deal on the new Nexus. Good luck finding another phone with specs anywhere near this good for US$350 off-contract. The GS4's off-contract price varies, but $630 seems to be the default. That's an 85 percent premium over the Nexus 5, which is arguably the higher-end phone.
Wrap-upThe unfortunate thing is that right now, the easiest way to get the Nexus 5 is to buy it on-contract from your carrier. You might still get it for cheaper than the GS4, but something is diminished when you're signing your life away for two years in order to get it.
If this plays out anything like the Nexus 4 did last year, then it might be at least a couple of months before Nexus 5 inventory catches up in Google Play. We'll have to wait for our review to offer our assessment of the Nexus 5, but from where we stand now, we wouldn't be surprised if the $350 version from Google Play is, dollar for dollar, the best smartphone out there.