Guys, I've probably been climbing on a Vt longer than most of you, probably nearly 10 years. While I love it, I've just switched to a knut, and will likely stick with it for these reasons:
1: Less slop!
2: It always grabs, whereas a loose Vt, the way I like them, often needs to be quickly set after climbing up. For instance if you are body thrusting up a ways, one hand above and one below the knot, if you lean back it won't grab. The knut seems to set much more easily and consistently.
3: It breaks and slides almost as easily as a Vt.
4: It works great for a lanyard, and in both uses, works fine with no slack tender. Just run the line through your biner.
For speed climbing, the Vt is probably a bit better...not sure, as I need to try the knut with about one more inch of length to see how that works. My current tress cord is kinda short, but when I tried to go with 3 instead of 4 upper wraps, the knut would not hold. So I know it is sensitive to length.
Thank you Knut Foppe!!