I really don't want to hate Snapkey's Si Evolution keyboard. It's innovative, and as the forward thinking individual that I tell myself I am, I want to be encouraging. But here's the thing, innovative solutions should fix something. That's why they're called solutions in the first place. The Si Evolution keyboard is kind of cool, and given enough devotion, it might even speed up your typing, but it simply breaks more than it fixes.
SwiftKey X is arguably one of the best keyboard alternatives for Android, and it's only getting better. The newest alphas (VIP login required) for both phones and tablets include a much-needed feature for any keyboard: multitouch. This will allow for even faster typing, fixing one of SwiftKey's biggest issues - missed and repeated letters.