I have a Vortex Solo. I like the size and volume but it has not good quality glasses, not clear and brighty. With excellent weather and a sunny day all works well but use it at dawn or dusk and the monocular will show the lack of quality of the glasses.
And Yes, is very tiring for long, and short, periods of time. Maybe it can be used for treestand hunting but one pocket binocular is a better option.
Actually is used for my sons, 6 and 3 years old, as they loved it, very simple to use and focus. I have several products from Vortex but this one is very limited.
Sorry for my english