Gauge: 1.23mm
Tension: 21/20 kgs (~46 / 44 lbs) for clay court at moderate temperature, strung with Wise Tension Head, slowest speed, constant pull
Racquet: Wilson Pro Staff RF97 Autograph
Estimated number of ball contacts to date: 1,000
Stringing: Tough! String is so edgy it would slip through the clamps (despite tightening), and at times even through the tension head. Also cut into the fingers a bit. The sharpness reminded me a bit of the Dunlop Black Widow, which however wouldn't slip, and seemed stiffer.
Playing: Spin is pretty good, but not as extreme as the rating would suggest. It did feel like the string eats up a good amount of power on impact. That made it somewhat comfortable, but didn't allow me to hit a heavy ball. I switched back to racquets strung with the Tour Bite and the Cyclone for comparison, and found both strings to deliver more power, provide more solid feedback, and produce a similar amount of spin.
Personal takeaway: Switching to the Ultra Cable would sacrifice too much power without overcompensating that with additional spin. Wouldn't enjoy stringing it frequently either. Will stick with the orange Cyclone for now.
General thoughts: I can't shake the impression that the Ultra Cable might have been developed to top the "spin potential" list. Tennis Warehouse calculates spin potential using string-to-string friction and ball grab, both of which seem to be very high - subjectively as well. I'm not sure whether many players would stick to the string for the long run. Appreciate the effort though - the Ultra Cable is probably going to push other manufacturers to come up with competitors, and maybe WeissCANNON's next iteration will be a long-term winner...
Too see how this string performs in context, check out my comparison of interesting strings in 2016.