I wasn't going to bite on this thread but I can't help myself....
There was a time I said straight for the field and angled for the range, but after using a couple angled spotters in the field I prefer angled. Fourth point mentions about rain/snow on the ocular of the angled and that is a consideration. Angled are easier on the neck and can be lower on the tripod (or in my case the monopod) and finding a critter with the angled isn't as hard as I thought it would be.
Scanning. There have been plenty of times when 8x or 10x binos don't cut it and a proper, versatile spotter is necessary. Big eye binos have their place in some types of hunting but in mountains they are like carrying a folding lawn chair, and don't cut it when a guy ends up back in the timber. And still a guy still has to carry a spotter to zoom in to get a good look.
The problem with most spotters is the manufacturers insist on eyepieces that start at 20x or 25x. Too much magnified movement when when moving the spotter around and too much magnified tremor. A versatile spotter should start at 15x or lower and it needs excellent eye relief and a decently wide FOV to be versatile and scan with. Plus I have yet to meet a spotter 65mm or less that doesn't start losing resolution beyond 45x or 50x. Even my Swaro or other alpha spotters of that size. Eyepieces should start at 12x or 15x and end at 40x or 45x and then it would be easier to have a wider FOV. But alas, magnification sells just like magnum rifles used to sell.
Having said all this, I'm giving serious consideration to sell my Kowa 553 and buying the Leupold 60mm, even though the Leupold is straight.
It's kind've hard to argue with Mule Deer's duovids though..........
