There are two things that keep my wife and me tethered to Google Chat as our primary means of texting each other:

1) Search. This is the big one. The fact that I don't even need to differentiate between email and chat when I need to search for something is highly valuable. Plus, its search functionality is just in general very solid. Go figure.

2) Integration into GMail. During the workday, it's more convenient for me to text from my laptop than from my phone. During the evenings, it's often the reverse. The fact that I can easily have a conversation going in my browser, then easily transition the conversation to my phone, is quite useful.

That said, I would love to be convinced that some of the alternatives mentioned in the article can either match or make up for these key features.