(You knew this was coming, right?)
Comparing feature lists and statistics doesn't really work on Apple's products, because that's not what makes them sell.
Selling on feature lists only works if you're trying to differentiate your product from a pack of close rivals in the same niche. Apple 2.0 — post-1998 — sells by inventing a new niche and then defending it, by staying out in front of the pack of me-too products.
So what's the new iPad like?
What I can tell you is: it's a little fatter than the iPad 2, and a little heavier. A new iPad minus the smart cover is about as fat and about as heavy as an iPad 2 with the smart cover. Existing folio cases for the iPad 2 fit the new iPad, although they may be a bit tight. It slid into my ZaggFolio (which I swear by, because it's the best bluetooth keyboard case I've yet found for the iPad in terms of keyboard feel) reasonably easily, but getting the new iPad out of it again required some muscle power (and a death grip on both the back and the front of the iPad).
Speed: is the same as the iPad 2, subjectively. (No surprise, as all the extra performance of the A5X goes into servicing the extra pixels.) Battery life is, well, not obviously different. (I haven't had it long enough to run it down.) Camera: again, I haven't used it yet, but it's supposedly the same unit as in the iPhone 4S, so no surprises: a jolly good snapper for a portable device that isn't marketed primarily as a camera.
Speech recognition: I haven't spent much time with it. You hit a keyboard button and start talking to your iPad. Then you hit it again and it transcribes what you said. This doesn't seem terribly useful to me in its present state, but I will note that in my test dictation it missed two words and didn't mis-transcribe anything. It's much easier, when editing, to spot a missing word in a sentence than to spot the wrong word in a sentence. As a writer of fiction, I'm going to experiment with using speech recognition as a tool for capturing dialogue, while using the keyboard for interstitial/descriptive prose.
Broadband: there are no LTE networks in the UK. I bought a pre-paid data-only 3G SIM from Three, pre-loaded with 12Gb of data (valid for 12 months), and used a SIM Clipper to cut it down to fit the micro-SIM carrier. I chose this option because mostly I'll be using the iPad where there's wifi — the 3G SIM is purely for emergency roaming, so I wanted a long expiry and enough data to cover 1-2 days a month of intensive use (for example, while staying in one of the many hotels that charge £15/day per device for wifi).
Which brings me to the bit you've all been waiting for:
The retina display is gorgeous. It has a higher contrast than the iPad 2's display, so even classic iPad apps look a bit brighter and more colourful. Weirdly, it's when running a retina-ready iPad app that I felt a little disappointed at first; the old iPad screen wasn't bad, unlike my eyeballs, and at arm's length I wasn't usually aware of the pixels.
What drove the improvement in quality home was reading. The Amazon Kindle app is retina-iPad compatible, and switching from it to a different ebook reader (Stanza) using the same typeface size made it glaringly clear that something was going on with font antialiasing. Simply put, reading text on the screen using an ebook reader app on the iPad is indistinguishable from reading on paper (except for the backlight). I'd rate this as a better reading experience than any e-ink device I've tried. And as I've only got the one pair of eyeballs, and they're not getting any better, that feature alone was well worth the price of entry as far as I was concerned.
The important point to note is that the virtue of the iPad 3 display is entirely dependent on the apps supporting it. There's a flood of re-compiled retina-ready apps coming through the app store right now (it started about 48 hours ago), and for text-oriented apps the process looks (from the outside) to be quite straightforward, but I suspect a lot of iPad games (especially the less profitable ones) may not see an upgrade. Games rely on artwork, and while art that was prepared offline can be rescanned (I'm thinking hopefully about Machinarium here), some may not be available in any higher resolution and may have to be re-made from scratch.
As to what it's good for ...
The iPad was launched as a media consumption device, but it's mutating rapidly into a proper computing platform. Yes, there's a walled garden for apps: some folks find this more than a little annoying. But as someone with eighty-something relatives to support, knowing that they can't easily shoot themselves in the foot with their computer is actually a plus point. Meanwhile, the restrictions on what can be sold via the app store appear to be relaxing — as witness, for example, this Python for iOS. At the iPad's launch, the official word was "there will be no interpreters on the iPad, ever". And now they're happily selling IDEs. You can start by selling a locked-down platform and then open it up gradually, but you can't go the other way; so I expect the iPad to slowly become more useful for general-purpose computing over the next year. And there are some forthcoming apps that I'm rather eager to see: Scrivener for iOS, for example. (Scrivener is a really nice book-oriented authoring tool for OSX, and now Windows and Linux; having an iOS version with Dropbox support would make my day because at that point the iPad will turn into a full-fledged author's tool, lighter and more portable and with better battery life than any laptop I've met.)