The biggest thing in any spotting scope other than the quality of the glass that they use is objective size divided by power factor to give you the average size of the exit pupil.
It is a common equation that will let you know what you are really looking for. For example, a 12X binoc with a 60mm objective will give you a 5mm exit pupil which will tell you how much squinting you will have to do. Not much in my case and I wear glasses. Do you?
Tasco, was always a problem with me as well, and I will never own one, after having looked through my buddy's scope. I have seen guys buy two spotting scopes and collimate them to become binoculars, because binocs are easier on the eyes, bc you dont have to squint the other eye. I shoot at a 1000 yard range from time to time and some of the guys have done this with older Bausch and Lomb spotters because they can individually focus each eye to their own specific handicap. I think that SWFA even had an example of someone doing this very thing a few months ago. He did it with a pair of Swarovski's.
Ask Chris, he would know.