First impressions:Purchased the Vortex Optics Crossfire HD Binoculars, 10x42 version.I bought these binoculars for bird watching, which has specific requirements as opposed to sports events and nature hikes. I wanted a large enough magnification that I could easily see the birds, but also with a wide enough field of view so that when a bird hops from one branch to another – something they are prone to do – that they wouldn’t be lost out of frame. I also wanted a fairly light weight and sturdy construction, all of which I found in my choice.These binoculars provide a crisp, clear image with no refraction. That is no colored fringes near the outer edges. The aperture is large enough that there is plenty of light gathering ability. Focusing is easy and natural, with the dial centrally located.This line is advertised as light weight, and it is, compared to other brands, but still it’s noticeable when hanging around your neck. This is not a complaint.CHOOSING MAGNIFICATION:For my whole life I’ve chosen and used bargain basement binoculars, usually 8X magnification. I thought 10X would be marginally better, but experts claim that when you use anything over 8 times, then the image can bounce around from your hand movements and shaking. I didn’t choose the 12X for that reason. The 10X that I purchased has noticeable jitters if held with one hand, but not so much that you lose track of the image. I’m glad I didn’t get the 12X. I’m quite pleased with the 10X, but I think I’d be just as happy with the 8X.CHOOSING FIELD OF VIEW:As mentioned above, I want the objective lens diameter to be large enough so that if a bird is on the move it would be easy to track and not fly out of range. The 42mm turns out to be perfectly suited to my needs. The next step up, 50mm may have made the binoculars bulkier and heavier, so I’m happy with this choice.ADJUSTMENTS:The inter-pupil distance adjustment was easy and intuitive. If the left and right sides are not adjusted to your eyes, you will see dark edges on the sides of the image. Once adjusted you don’t have to worry about this, unless you accidentally jar the adjustment.The diopter adjustment, likewise, was simple and intuitive. Once set up (if one of your eyes is weaker than the other) you can set once and forget about it.The neck strap was easy to install and adjust. No problems there.As mentioned in other reviews, the body strap for the carry bag it just too complicated. It reminds me of a medieval torture device. I discarded it and purchased a simple shoulder strap.MINOR COMPLAINT:I found that to see clearly through the binoculars and get a full field of view, your eye must be positioned exactly in the center of the eyepiece and at a specific distance from your eyeball. For me, this required me to hold the eyepiece about 3/8 inches from my eye. I found that resting my forefinger on my forehead, and the binocular eyepiece on the edge of my finger accomplished this nicely. The problem, however requires a more comfortable and reliable solution.I purchased a pair of 42mm rubber eye cushions that did the trick. That size rubber buffer is standard for microscopes, and are available for about $10 on the internet. See photos.CONCLUSION:All-in-all, I quite satisfied with this excellent product. It has made my bird-watching experience much more productive and enjoyable.