Had a chance to hit with the yellow 17ga today. It plays firmer, as expected, then the 18ga teal, but still plays softer then the original. I actually like the yellow 17 better then the teal. I found it offered all the same nice playing characteristics of the 18ga, but seemed to add a little more bite on the ball. The control was also better. I felt I could really hit out with confidence. The 18ga teal may offer a little more pop, but the yellow has even better control.
If the playability stays good for a few weeks, I would say this is my new string.