With the suggested combination, it is just as easy. When you receive a SMS, it will be notified on the desktop as any other IM you receive. Simply typing your response in the text input, will reply to the last received SMS.

I really like the UI of texty, e.g. threaded conversations. That is, as far as i know, not possible with GTalkSMS.

Overall, any seamless interaction with my phone from my desktop is greatly appreciated.