Since I didn't see a topic on the Modulus linesets, I figured I'd go ahead and start one.
I'm still a relatively new flyer, less than 2 years total. I spent all of last year flying around on whatever 'included' linesets came with the beginner kites I'd started with. For getting the feel of the tricks, the fairly simple 65'x90# lines that came with my Jazz were great for pretty much any kite I was flying.
But, since these are value-add bundle-ins, they're not the highest quality.
The Modulus lines, on the other hand, exude professionalism. I ordered a set of 75'x90# lines, and the first thing I noticed when they arrived was that the line diameter was much closer to what I have been used to seeing on 50# lines. But, unlike my conventional 50# sets, these have yet to snap. They're strong, even up past the 15mph wind speed, and come perfectly equalized from the factory (nice, since they were the first lines I've had that didn't require some equalizing right off the bat).
The blue/red color coding is a little odd. Most of the time, I'm flying in a grassy field, and it seems like my eye loses both the red and blue in the grass, they just don't stand out. When I've got them up in the sky, the combination of the thinner diameter, and the blue line against blue sky seem to make it impossible to see how they're twisted, to try and spin them out the other direction.
Overall, I've been happy with them, but I do wonder if I'm spoiling myself for other line sets? Will I be able to switch between these and stock spectra? Time will tell.