I purchased the Vortex Viper HD 10x50's a few years ago and can't say enough about the quality or price on them. The color definition is amazing for the mountains here. I just spent a few days in Yellowstone using them to glass along with a spotter. I always have the binoculars with me, the spotter is only if I have it. I use the binoculars to do all of my main work then the spotter to verify more detail at much further distances. With the color and edge definition of these it is amazing of what I can pick up and see at all hours of the day and low light glassing is amazing. Yes Swarovski has an edge on them but at 3x the price. Cannot say enough good things about them and recommend them to nearly everyone after using countless other brands.