It would be easy to say they are pretty similar to the 8×42 with a bit more power and leave it at that. The reality is that they are very much different. Visually the 8x and 10x look and weigh the same. There are a couple of big issues that I noticed on testing. The depth of field is dramatically reduced. This means you will need to work hard with the focus wheel to keep everything sharp. Also eye relief is not that great. I found I had to keep them fully twisted in, or on the first increment (even without glasses) Forget twisting the eye cups fully out, as you simply wont get a full screen image.
Don’t let the above put you off however. They have the same great optics, handling and cool looks as the 8×42 discoveries. Ideal if you prefer looking further afield , and dont mind the narrower field of view.
Optically, these are a serious contender to the superb Barr & Stroud series 4