Well, in short, not a huge amount. The design and display are the same, but there are a few improvements here and there to ensure things are kept fresh.
We've run down all the differences between the two tablets to save you scouring the spec sheets.
New iPad (2018) vs iPad (2017): Design
Side-by-side you're not going to be able to tell these two tablets apart.
Both the new iPad (2018) and the iPad (2017) measure 240 x 169.5 x 7.5mm, which we've found is manageable in the hands, if a little bezel heavy around the screen. You won't find the slightly thinner bezels of the more expensive iPad Pro 10.5 here.
The Wi-Fi only versions of the slates both weigh 469g, and it you opt for the Wi-Fi + Cellular models you're looking at 478g.
You'll also find a physical home key below the display on both generations, with the Touch ID fingerprint scanner built into them.
The good news is that the new iPad (2018) keeps the 3.5mm headphone jack.
New iPad (2018) vs iPad (2017): Display
Apple has stuck with its popular 9.7-inch display size for the new iPad (2018), and again it's the same as iPad (2017).
You also get the same 1536 x 2048 resolution and 4:3 aspect ratio. It may not be the best ratio and resolution for watching widescreen movies, but overall the screen is very good for surfing the web and reading, so we're not surprised that Apple has stuck with what it knows on both of these tablets.
New iPad (2018) vs iPad (2017): Power and OS
Now here's a change! The new iPad (2018) comes with Apple's A10 Fusion chipset, while the iPad (2017) uses the older A9 chip.
The A10 Fusion is paired with Apple's M10 motion co-processor, where as the A9 again gets the older M9 alongside it.
What this means is the new iPad (2018) is the more powerful slate, and it will be better at coping with split-screen usage, augmented reality, multitasking and gaming.
Apple doesn't reveal how much RAM is puts in its tablets, but it's assumed that the new iPad (2018) has the same 2GB as its predecessor.
New iPad (2018) vs iPad (2017): Cameras
Snap! That's right, you've guessed it, both the new iPad (2018) and the iPad (2017) have the same camera offering.
That means you get an 8MP camera on the rear with a ƒ/2.4 aperture, five-element lens, HDR, auto image stabilisation and full HD video recording.
Around the front, you'll find a 1.2MP Facetime HD camera with a ƒ/2.2 aperture and a Retina (screen) flash.
New iPad (2018) vs iPad (2017): Battery
We don't know for sure how big the battery is inside the new iPad (2018), but considering it has the same frame size, screen and camera modules as the iPad (2017) we'd expect them to be the same.
Apple quotes up to 10 hours battery life for both tablets as well, which further points towards the same size, 8,827mAh battery capacity in each.
New iPad (2018) vs iPad (2017): Pencil Support
One of the big differences between the two tablets is support for the Apple Pencil.
While the stylus won't work on the iPad (2017), Apple has included support for it on the new iPad (2018).
Previously the Pencil has only worked on Apple's iPad Pro line of tablets, so it's good to see the support filter down to the cheaper tier of slates. The new iPad (2018) will also be compatible with third party stylus options such as the Logitech Crayon, though stylus is limited to schools, not for consumers.
New iPad (2018) vs iPad (2017): Education
The key message at the launch of the new iPad (2018) was just how well suited it is for education.
It arrives alongside updates for Apple's Keynote, Pages and Numbers apps providing Apple Pencil support allowing users to easy annotate, sketch and doodle notes, while Shared iPad allows multiple pupils to have their own login on the same iPad.
The increased use of AR within educational apps will allow students to study in new ways, and teacher dashboards and controls allows educators to keep an eye on the progress of their pupils.
The additional power inside the new iPad (2018) makes these experiences smoother, but Pencil support aside, there's a chance these software upgrades could be rolled out to the iPad (2017) as well.
New iPad (2018) vs iPad (2017): Price
When it comes to pricing, it all comes down to where you live in the world. For those of you in the US and Australia, the new iPad (2018) for consumers will cost the same as the iPad (2017) did.
There are two exceptions to this. First, US schools will be able to order the 32GB New iPad (2018) for $299. Students and educators can also find a 10% discount through the Apple Store with verification.
Second, the UK price for the New iPad (2018) also gets a treat: a £20 reduction in price, whether or not you're a school or student/teacher. It's the one place in which consumers see a discount.
In the end, the 32GB, Wi-Fi-only new iPad (2018) costs $329 (£319, AU$469), while the Wi-Fi + Cellular model at that storage size is $459 (£409, AU$669).
If you'd rather treat yourself to the larger 128GB model, you'll need to part with $429 (£449, AU$599) for the Wi-Fi only slate, and $559 (£539, AU$799) for the Wi-Fi + Cellular option.
The new iPad (2018) is a better tablet than the iPad (2017), especially when you consider it costs the same (and in some cases slightly less) - but the differences are minimal.
The increased power under the hood means the new iPad (2018) will have a longer lifespan, while the Apple Pencil support gives it greater flexibility and functionality.
That said, if you already own an iPad (2017), there's not enough here to justify the upgrade and if you're in the market for an affordable iPad you may be able to find some good deals as retailers look to shift the older stock.