I've had two 99S frames for a couple of weeks now. Now, on the 4th and 5th string setups now, and WC B5E / WC Silverstring taken over as my new favorite setup at 52 lbs. The strings move right back in place very well. I was skeptical of this combo, but is works for me.
Just ordered another reel as I used my last 1/2 set of B5E today with the MSV Soft Hex. Soft Hex doesn't feel as soft as B5E/Silverstring, but I hit the the Soft Hex within hours of stringing when I normally wait a day to let the strings drop tension naturally overnight before hitting.
I didn't care for the Tonic Gut / Yonex Poly Pro Tour 125 setup, as it never felt right. I keep going back to the full Poly Pro Tour frame until I cut both the gut/poly and Yonex Poly out, and tried the Weiss Cannon setups. The frame 99S does hurt my arm when I try to play my normal routine of Sat/Sun/Mon/Tues am before leaving town Tuesday evening, so I have actually stopped playing any doubles with the 99S and only use it for singles.
Earlier today I added 5 grams of lead and upgraded to a Wilson Pro Hybrid grip that weighs 20oz cut to fit, compared to 12 oz stock Sublime grip that comes with the frame. Net increase of 13 grams per frame (all in the handle) so each weigh in at 336 grams and feel much more solid. Hit about 30 minutes tonight with a buddy, and the additional weight makes this frame feel better to me.