So I have 3 K Six.One Teams and 1 BLX Six.One Team. I weighed them and checked the balance the other day. Here they are: 1) 313 grams, 13.8 inches. 2) 305 grams, 13.37 inches. 3) 307 grams, 13.62 inches. BLX) 314 grams, 13.25 inches. Now I weighed them all up to 320 grams, even balance, and SW of 333. (Thanks to TW's customization calculators and tools)Two of the K factors were strung with Kirschbaum Pro line 2 Black 16, one was a hybrid of Topspin Cyber Flash16 with Forten Sweet 16 in the crosses, and the BlX had the hybrid as well. The Kirschbaum was strung @ 55, the hybrids @ 55 mains, 53 crosses. Here's my review(First time reviewer) Groundstrokes: I could hit much heavier with the lead tape, and go all out with the full poly. Topspin was much better with the lead tape, and so was plowthrough. I did find that I sprayed shots with the hybrid in the K-Factor. The Blx was not as lively, but I still missed quite a few long. I found the BLX to be better for flatter shots. Maneuverability took a bit of getting used to because of the higher swingweight, so I had to make sure my stroke was efficient. Slices were even better with the lead. I could hit good slices against hard strokes. And the stringbed really grabs the ball with full poly. With the hybrid the ball didn't seem to stay long enough on the strings. Spin was better with the K-Factors than the BLX. Volleys: Really solid now! Maneuverability was fine. Again the full poly was better because the hybrid was too lively. I also prefered the K-Factors touch compared to the BLX. Serves: This was one area where I preferred the hybrid, as I found a bit more power.(I am 5 foot 4, 14 years old & 90 pounds). At first I had a bit of trouble swinging fast with the extra weight, but adjusted after 15 minutes. That said, when I started swinging faster, my serves were heavy. Kick serves were easier with poly though. And the K hybrid had better kick than the BLX hybrid. Flat & Slice serves were better with the hybrid. I did like the BLX a bit more for flat & slice serves. Return of Serve: This was one area where both string setups were fine. I liked both equally. Solid, no twisting & just enough power. I did prefer the BLX for ROS because of the muted feeling. Overall: I preferred the K Factor to the BLX as the BLX was too dead and not as spin friendly. Both were much more solid with the lead and could hit heavy. I also found that full poly was better than the hybrid for me at least. I'll be using Pro Supex Big Ace next time because it's cheaper and supposedly a bit softer than Pro Line 2. Hope this was helpful.