I just got my set of cables done. Overall I'm very impressed with the quality for the price! I haven't been able to listen to them yet because I don't have my NX-treme's built yet and don't have any other speakers with tube connectors.
I did want to just mention a few things that I think could improve this kit if Danny or someone else at GR research is reading this. First, the solder I received was only about half as much solder as I needed to do both of my cables. Not a big deal, but it would have been nice since it's included to have enough to finish the job. Second, and this is the important one to me, the red and white heat shrink tubing included in the kit is just too small. It just barely fits over the separated strands. I ended up lubing my wires with wire pulling lubricant in an attempt to pull the heat shrink down as far as possible, but it just didn't go far enough. I spent almost as long trying to pull heat shrink as I did on the rest of the cables! Some slightly larger heat shrink would make these a breeze to build.
Can't wait to listen to them!