Rob, many birders prefer 8x because of the lighter weight and wider field of
view.

I prefer 10x because of the greater magnification and detail. I have poor
eyesight. I can find a bird easier with 8x but it doesn't do me any good to
find it if it's still not magnified enough for me to see details. I use a
pair of 10 x 50. They are roughly the weight of an anvil but they collect
enough light and supply enough magnification that I can see birds reasonably
well in low-light conditions. Or they used too. They been dropped, banged
around, left outside in the rain, etc. too many times and have nearly
reached the end of the line.

I also use a harness (a "bra" as some birders call it <g>) instead of a neck
strap to avoid spinal dislocation after a long day of birding.

Kelly