The Meopta S2 is a great piece of glass, it’s on par with the Swaro and Kowa glass. Really depends on what a person wants. I love my S2, the body isn’t huge but at 82mm it offers an excellent image and it fits in my spotter pocket well.
IMO the ATX line is too heavy and bulky unless you plan to be modular. The only way I’d consider them is if I planned going BTX. For a spotter they’re heavy, you can carry a much larger spotter for the same weight penalty. I personally don’t like the Kowa dual focus, they easily get hung up on stuff and are always out of focus when you pull them out. I prefer the barrel focus, it’s just more sleek and fits in the pack better. I’ve never felt I need the fine focus to get a crystal clear image.