I'm surprised no one has yet to respond to this message. I don't have either knife but would really like to own both. However, in my opinion, these two knives are really built/designed for entirely different purposes, but I don't want to put words in the maker's mouths. I've not held a TTKK but I have held a black widow and the widow is light as a feather.
For what purpose/use do want the knife? What will the knife be used for most of the time, if at all? If you can honestly answer those questions for yourself then it puts you much farther down the road in answering the design and materials questions.
Hope that helps some.