For me the two
biggest gripes with the iOS keyboard when using my ipad:
1) the fact that when a word that should
not be replaced gets automatically replaced (which can happen if you type very fast *duh*), you don't get the option to get the actual word you typed back. So then I have to delete the replaced word and type again what I had previously and make sure it does not get replaced again. On android, when I hit delete once (automatically inserted space) and the cursor is after the last character of the new word, I get the option to replace that again with the original word, that's two taps, 1 second.
Disabling the auto replacement is annoying too, because from time to time is does what it should.
there is/was a tweak in cydia to reverse the behavior of the auto replacement (only replace if you hit the suggestion), but yeah, I don't use my ipad enough to bother with jailbreaking it again.
2) In iOS the keyboard does not automatically realize the language I'm using, which is highly annoying if you frequently participate in forums/sites with varying language. On android I just type whatever I want, the system detects the language and gives me the correct (predictions/corrections). If I WANT to change the language manually, I just swipe over the space-bar, while on iOS I have to hold the language button (when I just press it once I always get the emojis, which I also use from time to time), wait for it to open (which can take some time), and then select the correct language (and repeat that every time you switch the environment)
For people who type a lot, the iOS keyboard is just infuriating. I just coped with it until I switched to Android as my smartphone OS (obviously) and found
Swiftkey for Android. When you have seen how good it can be, you get mad when you use iOS and type anything.
The thing is apple talks about how they care about the developer. But when using this, the developer has to make sure that his apps use the API, he has to change his code to get these functionalities, where on android I just download and install swiftkey and the keyboards across the os are instantly replaced.. c'mon

it's 2014, the technology is there

. I still like my ipad3, but I almost prefer going to forums on my motog, because typing is just so frustrating