I've now had a chance to play twice(about 1 hour each time) with my local pro with the 99S. I seem to echo the comments of most of the other posters on this forum. It was strung with full bed 4G. It was a very easy racquet to play with and no arm issues at all(I don't have injury history, but was concerned as I'm approaching 50). Played very solid, no instability noted, great spin with higher net clearance, plenty of power. Definitely going to order one when available in January.
One quick question. The thread is getting long, and I can't remember if anyone has played and compared it to the regular Steam 99. Would appreciate any thoughts comparing the two.