I'll agree that th ELs are more comfortable to hold, but the difference in weight in 10x42 is only 3.2 ounces. Here is a comparison chart from Swarovski's website. The 10x42 EL is listed first, the 10x42 SLC second.
Magnification 10x 10x
Objective lens diameter (mm) 42 42
Objective lens diameter (in) 1.65 1.65
Exit pupil, diameter (mm) 4.2 4.2
Exit pupil, diameter (in) 0.17 0.17
Eye relief (mm) 15 14
Eye relief (in) 0.59 0.55
Field of view, real (m/1000 m) 110 110
Field of view, real (ft/1000 yds) 330 330
Field of view, real (degree) 6.3 6.3
Field of view, apparent (degree) 63 62
Shortest focusing distance (m) 2.5 4
Shortest focusing distance (ft) 8 13
Diopter compensation (dpt) +-3 +-5
Interpupillary distance (mm) 56-74 56-72
Interpupillary distance (in) 2.2-2.91 2.2-2.83
Twilight factor (DIN 58388) 21 21
Length, approx. (mm) 158 147
Length, approx. (in) 6.22 5.79
Width, approx. (mm) 123 122
Width, approx. (in) 4.84 4.8
Height, approx. (mm) 64 71
Height, approx. (in) 2.52 2.8
Weight approx. (g) 780 870
Weight approx. (oz) 27.5 30.7
Color gr?n
Color green