[Samsung Epic 4G Touch] Capp5050:
I've been testing a LOT of keyboards, and for me, the BEST keyboard would actually combine some of the features of a handful of my favorites.

SwiftKey is one of those favorites, for one reason - text prediction. Now DON'T get this confused with text prediction that most keyboards have, where they take an educated guess at what you are trying to type and suggest the complete word.

SwiftKey, in contrast, predicts the NEXT word you are going to type, BEFORE you've even started typing it - and it does it quite well. What?! The NEXT word?! That's insane you say...

It is pretty insane - but it works; it uses the context of what you're typing (e.g., the words typed previously) as well as your 'historical style' to predict the next words. As soon as you type the first letter of the actual next word, it then throws another set of predictions, just in case it was off. The result: fat-thumbed people like me end up typing less, because I'm using their suggestions plus 1 letter (to start a word) and getting whole sentences out.

There's a one-month fully functional trial version of it, so I highly suggest you check it out.

The ONLY other keyboard I've tried thus far that predicts the NEXT word is "A.I. Type Keyboard"; (the AI is for Artificial Intelligence). They only have a ten day trial, and the keyboard requires network access to 'get' some of it's suggestions. I haven't found this to create a lag, and it implies that their A.I. is better (since it's polling a machine somewhere), but I haven't found that to be the case yet, and with only a ten day trial, I'm not sure I'll have enough time to find out.

So then why isn't SwiftKey the ONLY keyboard for me?

Coming from a Blackberry, I am a BIG fan of one-handed 'hold-and-type' and Compact QWERTY is essentially the methadone for recovering Blackberry users. Unfortunately SwiftKey does not currently support it. In fact, one of the limitations of SwiftKey is that there are only 3 skins, and they are all the same (save for color). So in terms of customization, SwiftKey is a bit of a dog compared to others. That's why you'll find so many people who use it for some purposes (e.g., writing a long email), and then switch to another keyboard for other tasks.

Others (with my brief opinion);

note that I tend to avoid swype and favor Compact QWERTY; but Compact QWERTY can get a little tedious when not typing conversationally (i.e., filling in prompts) so a quick switch to full QWERTY is critical.

GO Keyboard - absolutely nothing special that others don't have. Can be made pretty, with lots of custom skins, but I don't care how pretty my keyboard is (that said, I love a lot of the other GO products)

Ultra Keyboard - This is my most-used keyboard, because it has Compact QWERTY and I can do a quick swipe to get to full QWERTY; it's got a ton of customizations as well; one of the many, includes a toggle for 'multi-touch' which is great. Unfortunately it was crashing on me recently so I stopped using it (new version just released, so hoping issues fixed) and began using:

Smart Keyboard Pro - Very similar to Ultra Keyboard (Compact QWERTY, swipe to switch, etc)., not nearly as many customizations, but close enough to get me through most situations

Thumb Keyboard - I like it, as others have stated above, since you have more 'real estate' to type with. But being an ex-Blackberry user, I really WANT and NEED to type with one hand - the same hand I'm holding the device in, and so the innovative 'separated keyboard' doesn't help because you really need two hands to use it properly.

ThickButtons - This is a WEIRD keyboard, but (like Swype I guess), if you can get used to it, it's pretty powerful, and I found myself typing surprisingly fast after a short period of time. Basically, as you type, the keyboard, on the fly, makes larger the next 'probable' keys, while making smaller, the 'less probable' keys for the given word you're typing. Seems weird, and frankly, if you look at the keyboard too much while typing, you'll confuse yourself. But if you just 'go with the flow,' you'll find that the next letter you're looking for is right there, inflated like a balloon, ready for you to hit it.

I've tried a few others, but not worth mentioning here because there wasn't anything 'unique' as most of the ones above have, to differentiate.

So I guess the ultimate keyboard for me would be one that includes all of Ultra Keyboard's capabilities and customization alternatives combined with SwiftKey's prediction model.

Hope my wasted time and obsessiveness is helpful!