Serena has been using the string since Charleston where she won.
Drakulie is right, many of the pro's are using this as a cross with gut. My suspicion is that it doesn't wear out the gut as quickly?
I play tested this twice and have it in my Juice Pro now. IMO you need to play this poly lower then the poly you are using now.
Serena and Venus are both 60+ with this string, but they are playing with a 100+ headsize. I played this at 60lbs in a surge and hated it.
I played it at 52 in my Steam and loved it. I have a hybrid in my Juice Pro of NXT control in the mains and 4G in the crosses 60/54. It is ok.
I think for most people the best thing to do will be a hybrid with it in the crosses or as a full bed with a very low tension in smaller headsizes.
The main reason I love the stuff is the comfort. I have been battling a bad elbow for the past few years and this is the first poly I can use in a full bed. I miss my ALU...