Use SwiftKey. It learns when you type texts, emails, etc. It's amazing. It really knows what you want to say before you say it.
I was at ATT trying to fix my texting issue. Certain people with iphones I wasn't getting their texts. Apparently apple realized my contact info was associated with an iphone. It was sending iMessages even though I didn't have an iphone anymore. ATT solution was to have that person delete my info and put me as a new contact. It worked with one person, but not another. I am getting irritated now.
I checked out the HTC 1 at the store again. I like the feel and balance in my hand better than the S4. I am looking forward to the newest version in Jan/Feb. The s4 is too big for my hands apparently. 1 handed operation isn't as easy as the HTC 1. Maybe the curve on the HTC helps hold it better.