I rode both the new ST and S3 last week. The ST, I put about 75 mostly highway miles, between 70-85 mph in a strong cross wind. Very, very, very fine machine. Could easily make me sell my Tiger.
The S3, I only rode about 25 miles, on a "controlled" test ride. But even then, you can tell that is on Hell of a machine. It has instant power, right now. Could easily make me sell my wife (kidding...).
Both engines (basically the same) were very smooth and the FI is flawless. Transmission are a step (or two) above my Tiger, again, very smooth. Both should sell very well.