So far SwiftKey is my keyboard of choice, but that's only because it has learned a bit of Polish, which the Apple keyboard couldn't manage. But I gotta say that the keyboards implementation on iOS is awful compared to Android (L on a Nexus). I've used my friend's Nexus to compare and OMG! How can Apple be so backwards when it comes to usability. Changing the keyboard on the Android L is a second, plus you can get into all the keyboard preferences while writing. As much as I don't like Android and it's messiness, there are some functionalities that are just done better - like I would expect them to be on iOS.
I'm just disappointed with Apple, with all their talking about "ease of use", "it just works" and how it doesn't matter "who's first", but "who gets it right first"... keyboards are really a poor area in iOS. It's great that they finally freed that element of iOS, but come on. That's not enough.
If I may offer a small digression: iPhone 6 seems to be great a phone and I'll be getting one, although I considered HTC for a moment. It's a step forward comparing to 5S and especially to my 4S, but damn it, I really expected something more. Like one of the media reviews stated (don't remember which title The Verge or WSJ), it's a disappointment in that regard that the iPhone 6 is just iPhone 5S, but slightly better, mostly just bigger. I was expecting Apple to truly redefine big screen phones, make an awesome screen, some useful system functionalities that will put the bigger screen estate to use. Meanwhile all we get is the landscape mode, which is cool but limited to 6 Plus and no multitasking. They done it with OSX - they were the first to make working in multiple apps easy and fluent as a breeze with how easy you can move between apps and even apps in full screen. It's really awesome for me.
How come they don't do it with iOS? Imagine working/playing with Safari and Notes/Pages. You copy something form the website and paste into a writing app instantly. Or you're just writing something and you can reference a website or another document at the same time, just like you would on a Mac. That's what I would truly want for my iPhone to do. Games and books on a bigger screen are awesome, but they're not a feature. They come with the territory. After tears of telling customers they don't need bigger screens, because the 4 inch is perfect for one hand use, they get scared of the market trends and put out bigger screen iPhones. And that's it. They don't even justify it in any way - in marketing terms so to speak, like" Ok it took us long enough, but now we'll show you what's the bigger screen truly for etc.
Android may still be behind, at least for me, it still looks messier and more hectic than iOS, but damn are they making progress. I feel like Apple has stopped trying. Instead of rethinking the iPhone for the bigger screen, something that would make me go: "Wow, so that's what a bigger screen can be used for, that's what you can/should do with it", they have just blown up the iPhone 5 (the bezels!) and called it a day.