Tension: 52lbs, my usual test tension for polys
Regular string set up: Discho Iontec Hexa 1.25 @ 46 lbs
Racquet brand and model used for test: Dunlop Aerogel 4d 300 Tour with leather grip + over grip and 27 grams of lead
Power of test string: Compared to other polys at 52, it was a bit lower powered. Probably because of the pre stretch, which i ignored because I didn't know how to consider the effect of it. It was probably the equivalent of 54-56 lbs. It certainly was not powerful, and at no stage did it become a cannon. I'll harp on that later..
Feel: This is its shining attribute. Excellent pocketing, and touch at net. It is tough to describe. Muted but crisp. Stiff yet soft. I don't know how to explain it. On groundstrokes, I felt like I know exactly where the ball was going to go depth wise. Drop shots were also hit to a great success. Nonetheless, feel was something that stayed with me throughout the playtest.
Spin: Being a round string, I knew not to expect much in terms of spin. However, I didn't really notice a lack of spin. I never once hit a ball long and said that it was because I didn't have enough spin. I felt I got less spin than an Isospeed baseline, and less of a penetrating bounce, but because I had the excellent feel, I never once needed the extra spin.
Comfort: I have never had any wrist/elbow/shoulder problems, and it stayed that way throughout the playtest. It did feel a bit stiff the first time I played with it, but it softened up for my second outing.
Durability: It is tough for me to comment on durability, because I rarely break strings in my 18 x 20 dunlop. However, I did not notice notching, so it should be fine for anyone.
Playability Duration: Kirschbaum really hit the nail on the head with this string. It played the same from the first hit to the last. Tension maintenance was also excellent. According to racquettune, right off the stringer it was 48 lbs. After a week in the bag and a hitting session, 44lbs. It astonishes me how it only lost 4 lbs. The prestretch definitely helped.
Control: This is why I loved this string. Perfect in this category. I felt that I could do whatever I wanted with the ball. Trajectory wise, the flight path was quite flat. I didn't get much of a grabby feeling with the ball, so I ended up swinging through the ball more, creating a flat trajectory. Nothing wrong with that; I think it in fact helped my game a bit.
Compare to the string you use most often: Compared to Iontec Hexa, it was worse. But not by much. WIth iontec, I get more feel, and the ability to change the trajectory of the ball. Not only can I hit flat with it, I can hit with a loopy spin. With the KSSO, I got a little less of everything, except tension maintenance. Compared to another round string, isospeed baseline spin, I got a little bit more in every category, especially tension maintenance. I think that with synthetic gut crosses, we could have something special.
Tension recommendations: After seeing how the prestretch effected the set up, I would string it a bit lower, maybe 48 or 50 lbs. Stringing it lower might open up some new doors, but at the very least it will help with the low power.
Summary: Hmmm. This is a string mainly for someone who doesn't want any help. You'll have to swing through, and you will find yourself up at net taking advantage of the exceptional feel. I do know that it is a round poly, but I would have liked a bit more ability to grab the ball. I felt that changing direction wasn't the best due to the lack of grab.
Looking at the reel price, this is certainly a contender for my next reel. I do think that there are better string for less $.
Also, the orange is a bit too fluorescent.