Few things...

I gave both Swift key and swype a try when apple introduced the third party keyboard extension... Due to iOS not handling it well, I went back to apples keyboard. Now on ios9 I gave both a try again. swype tried to predict way too much and even replaces the right word I typed when I type the next word which is really annoying. I think SwiftKey just does enough prediction and auto correcting I like it much more. But even sometimes that have trouble learning my vocabulary.

chuthan about Swype, v1.6.1