I love the whole SFL line. I'm not an optics expert, but I really couldn't tell any difference between these and EL 42s(no experience with the SLCs). I wasn't able to use them side by side with the 42s at dusk, but I'm really happy with what I've seen so far out of the SFL 50s in low light. Larger lenses/exit pupil and similar quality glass should mean SFL 50s will perform better in low light, but don't hold me to that. I much prefer the SFL's ergonomics and focus wheel. The focus wheel is a tad touchy on the 12x(still getting used to it), but great on 10 and below.