I bought the SLCs 10x42, Zeiss Victory T* FL 10x42, Nikon Monarch 7 8x42, and the Vortex Viper HD 10x42 all at the same time and spent a little over a month off and on in the field under varying light conditions. The Vortex was okay, but clearly not as good as the other three. The Zeiss and Swarovski were the best, so most of the month was spent comparing them. I ultimately picked the Zeiss and have never looked back. In the lowest light, the Zeiss are brighter; the SLCs may have had slightly better contrast. The biggest difference I saw was during bright light glassing towards the sun: the Zeiss had much better internal baffling to stop the reflective flashing. The Nikon's cost $1000 less than either the Swarovski or Zeiss but the difference between them was VERY small. I ended up keeping them too because I thought they were such a good value relative to their performance. In short, from what I've looked at, Zeiss is the best... but you would struggle to see the difference from a $400 pair of Nikon Monarch 7. So even though I use Zeiss, I recommend the Nikon's to most everyone I meet.