Funnily enough, I am looking at at 4.5 x 40 model. I had one in my hands at the local optics shop today, unfortunately not able to test in the dark
. Optical quality seems OK for the price at 4x, but the digital zoom is pretty ordinary. The unit is fairly bulky in the hand. A few reviews comment on how the focus is hard to manage, but it's not too bad, if you've ever spent a fair bit of time on bino's. I found using two hands, one to hold the unit and the other to focus was quite functional. I'm interested in why you would choose the 6x zoom, more money for it, the field of view is smaller. My gut feel is the 6x unit would be less versatile?