Yup, this is the one.

Nice review, BTW.

It is clear to me that all the "minor" keyboards lack the precise word prediction and swyping capabilities of the superior Swiftkey (by far the most accurate) and the contender Swype.

The reason is that these two features cost a lot of money to implement correctly: Swiftkey was co-founded by Dr Ben Medlock from Cambridge University with a doctorate in language-based artificial intelligence and now employs 100 people.

If you perceive how amazingly accurate Swiftkey sometimes predicts the following words, you know that a lot of work has been and still is being put into this prediction algorithm. On top of that Swiftkey by design only shows you a selection of three words to choose from. And don't forget: For every new language you pretty much have to start from scratch again.

I have bought Swiftkey, Swype, Minuum, and Thumb keyboards and tried numerous free ones but I always come back to Swiftkey. Though I also really like Minuum for small devices (tip: use the ABC layout in Minuum).

While I personally also find Swiftkey to be the best for pay keyboard on Android, I recently found a very good free one:

"Multiling Keyboard (new beta)" which is totally amazing, 320KB in size plus language packs so it comes in around 1MB vs. Swiftkey 16MB, no network permissions (language packs are on the Play Store), and probably the most customizable keyboard with a big number of tricks up it's sleeves (custom auto-completion of text blocks, swipe, custom keys, adjustable keyboard position, etc.)

I think this one is best for people who are concerned about privacy, since it has no network permissons.