When Swype was free on the Samsung Phones I was using them and thought it was the best, then they got rid of it and just had the Paid version so I decided that if I needed to pay I was going to see what else was out there, Google did a Sale last year on the Swiftkey for .99 and I bought it there, I haven't used anything else since then.
I've tried Google keyboard once or twice in that time but even when they have getting a lot better, and it looks and works a lot better, for me Swiftkey is superior, and now that Swiftkey is Free, it's a no brainer.