I just received my first LSL-S last week. I had never seen one before, although I had read most of the posts about the difference. Here's what my eye sees based on a comparison with my LSHs, shining on a wall.
The LSL seems to be just as bright overall. The hotspot is a little less bright, however, and the light is spread out more. The shape of the hotspot and the coloration tend to look like what I see from the Arc AAA. That is, while the overall color is white, the hotspot is bluer. And, it is circular, as opposed to the LSH's diamond shape. Finally, my LSL has a little ringiness to it; the LSH has no rings of light.
Paul