Actually i have posted this question in the iPad 4 forum at iMore.com. One of the very helpful replies is this from mulasien:
"Hello Soreloser, good questions. I'll try to give at least my input.
First off, given that you're already familiar with both iOS and Android, you're probably aware of the pros and cons of each OS in general.
I currently own an iPad 4, but also used to own an Asus TF300 Android tablet.
from your points:
- I doubt that you'll tell a difference in video from the iPad vs. the Nexus 10. There comes a point where a PPI count can't be determined by the naked eye past a certain point. The branding of 'retina display' gets its name because it (at least according to Apple) is at the PPI where you can't see individual pixels without putting your eyeball right on the screen (which I don't recommend). Both will look great.
- An iPad is a great product on its own, but goes up in value if you have other Apple products to sync with. I like being able to take pics on my iPhone, and have it automagically appear on my iPad's Photo Stream. However since you have an HTC One now, it doesn't sync up quite as well, although you can use apps like Google+ instant upload to sync pics between both devices
- While the Nexus 10 is indeed a beast in terms of hardware specs, it will still not be at smooth and lag-free as the iPad. This goes for all Android hardware. Yes, I'm aware that 4.2 Jellybean is a significant improvement for smoothness (I know, I had a 4.2 phone and tablet), but even then you WILL notice lag at some points. The question will be how much it irks you, some people are bothered by it more than others.
- Of all 10" Android tablets, I'd recommend the Nexus 10 the most. Gets updates direct from Google, and has incredible hardware to boot. I have no knowledge about the build quality vs. an iPad, so you'll have to google that yourself.
- The Android tablet app selection has improved a good bit over the years, but still lags behind iPad.
- Android by it's nature has more customization and better app communication than iOS, depends on how important this is to you.
- Although the Nexus 10 has a faster CPU, the iPad 4 is still super smooth. There aren't any apps out yet that actually tax it's performance. Also, iOS has been shown to be more optimized than Android (the nature of the beast) and runs faster even if it has a slower CPU.
With all that said, my personal take is that I used to own both an Android phone and tablet, but now have an iOS phone and tablet. Why? I was initially attracted to Android because of the customization and greater control you have over the OS, and the ability to have live widgets on your screen, all of which are nice. However, the lagginess of the OS, the inevitable "this app is not compatible with your device" that you WILL run into (even Nexus products), and lesser app (tablet) selection acted as a 'death by a thousand cuts' for me, and I made the jump back to iOS. Yes, iOS has less customization and no widgets compared to Android, however the trade off is that you get a rock solid OS with an amazing user experience and app selection. I did not miss what I gave up in Android for what I gained in iOS. The 'it just works' moniker is correct (except for Apple Maps, it still sucks

). That, and all your favorite Google apps are available on iOS as well (and in some cases, work better than their Android versions).
That's just my experience, your mileage may vary."
That same author also wrote:
"Some common deal breakers for each platform are usually as follows:
iPad (or iOS in general):
- Apple's closed system (walled garden) vs. Android's open system (this is actually a plus for some people, depends on you)
- unable to sideload apps from outside the app store/Play store
- unable to change default apps outside of Apple's versions (e.g. make Chrome the default browser, Google Maps the default maps app, etc)
- in addition, can't change keyboard. SwiftKey for Android is a wonderful, amazing keyboard. iOS' keyboard is the second best out there IMHO, but still not as good as SwiftKey
- no accessible local file system/storage, cannot store a variety of files locally (outside of photos/videos) for access by other apps. iOS apps get around this by either creating their own file storage in-app (usually accessible by only that app) or using cloud storage for file access (Dropbox, Google Drive, etc)
- stuck with a static app grid on home screen, no widgets, quick toggles, etc (though iOS 7 will bring quick toggles via the swipe up control panel)
Keep in mind that all of the above points are just a jailbreak away from being a non issue, if you're into that sort of thing.
Android tablet/Nexus 10 cons:
- selection of tablet apps still not up to par with iOS, though it has improved considerably
- many new apps tend to be available for iOS first, and then Android later
- cross device syncing not as good as Apple counterparts. It's not terrible, but Apple's device syncing is just incredibly good
- user experience in the OS will never be as fluid as iOS. It's improved (and should run fine on a Nexus 10), but a one OS for many devices setup will never be as fluid as one OS made for one device by the same manufacturer. Chrome on Android is especially bad about stuttering when scrolling down web pages - drove me nuts
- you will run into the occasional "this app is not compatible with your device" issue.
- malware is a legitimate concern on Android, but shouldn't be an issue as long as you stick to the Play Store for apps
- support for devices pales in comparison to Apple. If you have a hardware problem with your iPad (assuming it's still under warranty), take it to an Apple store and they'll either fix it, or just give you a replacement. Good luck getting that level of support with any Android device, including Nexus devices.
- while you can 'tinker' with Android more, be prepared to spend tinkering time just trying to troubleshoot annoying issues, like tracking down background apps sucking your battery dry. I work in technology in general, but even I got tired of always having to tinker with my tablet just to restore normal functionality.
That all being said, you need to look at what you need to use the tablet for and see what solution is best for you. There are people who have legitimate need of local file storage and being able to side load apps for their use case, and Android works best for them. In my own personal experience, the 'jankiness' of my Android tablet, app compatibility issues, and overall less fluid experience eventually drove me nuts. There are things I gave up going to an iPad (noted above), but in the end I don't miss them because the overall experience has been much more enjoyable despite the trade offs.
Again, your mileage may vary."