Two days, two new tablets. Who'd of thought that would happen? Apple has announced the new iPad Air 2 hot on the heels of Google announcing the Nexus 9, its latest pure Android device.

The Nexus 9 steps into new territory for Google and Android, while the iPad Air 2 evolves a model that's already very good. Crunching through the numbers, however, just what's the difference between these two rival devices?

The Nexus 9 was built by HTC, features an aluminium frame with a soft-touch grippy back. It measures 153.68 x 228.25 x 7.95mm and weighs 425g (Wi-Fi only). 

The iPad Air 2 has a larger display, but measures 169.5 x 240 x 6.1 mm and weighs 437g, with that premium aluminium bodywork. The iPad has a bigger footprint and almost an inch on the display, but is only 12g heavier than the Nexus 9. That's about the weight of a pencil.

Where Android normally eclipses Apple is in resolution, but the Nexus 9 and iPad Air 2 run closer matched. There is a difference in size, however.

The Apple iPad Air 2 has a 9.7-inch IPS LED display, with 2048 x 1536 pixel resolution, 264ppi. The Nexus 9 has a 8.9-inch IPS LED display with 2048 x 1536 pixel resolution, 287ppi.

Both devices offer the same resolution, but the Nexus pixels are tighter packed, so it might appear sharper. However, the iPad has an anti-reflective layer in the display, said to reduce reflections by up to 56 per cent compared to previous models. That might make it better for use outdoors.

Both devices have a 4:3 aspect. That's common for the iPad, much less common for an Android tablet.

The iPad Air 2 is a second-gen 64-bit device, using the new A8x processor with M8 coprocessor to handle motion, promising a 40 per cent CPU performance boost over the previous version, 2.5x GPU boost.

The Nexus 9 is the first Android device designed for 64-bit. It uses an Nvidia Tegra K1 dual-core processor and Keplar GPU, supported by Android Lollipop's 64-bit compatibility.

Of course both run on different software platforms and at this point it's impossible to judge which will outright be more powerful and how that will translate into user enhancement.

Adding a feature from the iPhone, the iPad Air 2 now has Touch ID. This replaces the home button, meaning simple fingerprint security, as well as convenient authentication for App Store or iTunes purchases.

There's no such thing on the Nexus 9, although Android Lollipop supports a whole range of new security features, such as using location, voice and connected devices to help the device decide if it's in safe hands.

We've never been wholly convinced by cameras on tablets. That won't stop people waving their wonderful slabs of technology around at tourist spots and Apple has increased the photographic abilities of the iPad Air 2 to recognise this. There's now an 8-megapixel f/2.4 camera on the rear, offering the sort of features you'll find on the iPhone 6, including timelapse, slow motion and more. If it's anything like the iPhone 6 in performance, it'll be very good.

The Nexus 9 also offers an 8-megapixel camera, and it's also f/2.4. Traditionally Nexus devices haven't had attention lavished on the cameras. We suspect that the iPad camera will give better results, but we'll have to put both to the test to see what sort of results come out. 

Whether tablet camera performance is an important factor for you is a different matter.

A world of difference, but the latest from both camps. The iPad Air 2 launches with iOS 8.1, the Nexus 9 launches with Android Lollipop. In terms of which is more exciting, we probably know the least about Android 5.0 as it's brand new, whereas iOS 8 is more familiar, as it's spreading across all of Apple's recent devices.

We'll not tell you which is better, per se, because your personal preference will be the biggest factor here. The Nexus 9 might enjoy a more open system, the iPad will have the most dedicated tablet apps. Both are slick, fast and packed full of features. In some areas, like notifications and sharing, we suspect Android has the edge. iPad users, however, will probably enjoy better consistency.

Perhaps an odd choice in a comparison of tablets, but the Nexus 9 comes with twin front-facing BoomSound speakers. The iPad Air sounds great in its own right, but we've always found HTC's BoomSound speakers to be class-leading. 

Does that matter on a tablet? Well yes it does. Watching movies, playing games or just sharing the latest YouTube sensation is richer when you have the sound to back up the visuals.

Apple hasn't declared the capacity of the battery in the iPad Air 2, but has confirmed that you'll get 10 hours of mixed use from it on Wi-Fi. That's the same for all the iPad models.

The Nexus 9 has a 6700mAh battery and Google say it will give you about 9.5 hours. That's pretty close.

The iPad has always been rather expensive, with cheap Android tablets offering a cheaper route to tablet ownership. The Nexus 9 will cost $399 (16GB), with pre-orders opening on 17 October, available from 4 November. The UK price has not been confirmed.

The iPad Air 2 16GB will cost $499 (£399). Apple may be bringing iPad prices down, but the Nexus 9 will be the cheaper option.

The iPad Air 2 arrives in safe territory, making safe upgrades to a tablet that's already hugely popular. Making those upgrades without bumping up the price over the previous model will make it enticing for anyone who has been holding off buying the iPad. However, with the existing iPad Air dropping in price, that might be the natural choice.

The Nexus 9 faces a slightly harder challenge. It's a first-gen 64-bit Android device, but it does offer a pure Android experience, free from the clutter that Samsung or Sony add to their devices. It's also cheaper, but we suspect that many will choose the iPad for it's established app offering.

One thing's for sure though. We can't wait to get these two new tablets in for review.