The interface is simple and slick and easy to use. If your a rapid typist who relies only on auto correction and what not, this might be for you. You have the ability to add words to the dictionary and add additional languages as they become available.
What I found while using the application is that it's not that great at auto correcting my words and predicting what I'm typing. Out of a normal size paragraph I was able to denote about only 60% accuracy. So what does this tells you? Just barely a passing grade.
On the other end the keys are large, spaced correctly and is perfect if you have fat fingers like I do. There's definitely place for improvement but this is a great start for this application.
For myself this wouldn't be a daily driver as I rely mostly on the swypping capability of Swiftkey and it's prediction.
Why not point yourself over to the Google Play store and try it out for yourself and make up your own mind right? This is the only way you'll really know if this is the keyboard for you.