OnePlus has crammed a sizable 3100mAh power pack into the One, and going over the performance of other handsets using Qualcomm's Snapdragon 801 chip, the signs are good that it will be able to deliver decent battery life here as well.
The smaller frame of the Nexus 5 means there isn't as much space to play with, and it makes do with a 2300mAh battery. We've found battery life to be pretty inconsistent on the Nexus 5, so we're hoping OnePlus has paid close attention to the unit in the One.
Neither handset comes with a microSD slot, so you're forced to make do with the internal storage supplied on the phones.
You can always take to the cloud with services such as Google Drive and Dropbox available - but that's not for everyone.
The Nexus 5 is available in 16GB and 32GB guises, although you'll need to chop off around 4GB on each to take into account the operating system.
Over at OnePlus you also get two choices, but this time its between 16GB and 64GB. As you'll see in a moment the price difference between the two storage sizes is minimal, so we'd recommend plumping for the full 64GB.
As we can see, both the OnePlus One and Google Nexus 5 are well equipped smartphones, but its their prices which really make them stand out.
The Nexus 5 costs £299, $349, AU$399 for the 16GB SIM free model, and £339, $399, AU$449 for the 32GB option.
If that sounds like a good deal wait until you hear this: the 16GB OnePlus One will set you back just £229, $299 (around $AU400). The 64GB variant is an equally affordable £269, $349 (around $AU450).
The Nexus 5, having been launched mid-way through 2013, is widely available both online and in retail stores so if you have your heart set on one it won't be difficult to come buy.
The OnePlus One has only just been announced and it's rollout plans are totally clear yet. OnePlus is running a competition to give away 100 devices and then is selling further units via an "invite only" initiative.
We don't know whether the OnePlus One will enter mobile markets worldwide, and it could well end up being rather tricky to get hold of. We'll just have to wait and see.