Not a scientific perspective, but I like both. That is, some jobs work better, imho, with high tension mesh and the subsequently thicker threads and some are best ran with the thinner threads at lower tension. Specifically, large, solid fill open areas with thick inks are not S meshes strong point.
S mesh, or any thin thread mesh I'm sure, does tend to get damaged more easily. So far I've been very impressed with the S mesh's ability to hold stable tension. Properly stretched the first time around, the upkeep is minimal just as it is with the Newman Roller Mesh or, presumably any quality, low-elongation mesh.
A good example was a job on Gildan hoodies I ran two days ago. Black fleece with a pretty big open area print on the back, white ink. Used a 150s with a lot of eom, about as much as the art could still resolve at. With a little warming and stirring, the Epic Quick White was flowing like butter. Had to jack the off contact up ridiculously high and still had issues with snap off. Prints looked fine, but my discerning eye didn't care for the way the ink surface looked up close and repeatability was much more difficult at such high oc and lower tension (I print manually). The trade off is that the same job, ran on the newman mesh at 50-55 n/cm would have had a much more even surface but, up close, you can see the mesh threads pattern just a bit.
I do enjoy the reduced drag of thin thread mesh and, as a hand printer, using fast strokes with less pressure.
How do you like the LX compared to regular 'ol S Pierre? I'm looking forward to trying some. Not a fan of white mesh threads though....I'm guessing that's why it only comes in the lower counts.