New to this site, which I’ve been enjoying very much - thanks, all. Weighing in here because I’ve become a bit of a monocular nerd in the last couple of years. I agree with pretty much everything in this thread; I’ve used the two little Nikons, the 8x and 10x Zeisses, and the 8x Leica. They’re all really good, but to my mind the class of the field is the Leica, which is about the same size as the Zeisses but has much superior optics. I’ve come to exactly the same solution as Crinklystarfish: a neck lanyard and a Zeiss case (the case the Leica come with is beautifully made but relatively large, and the macro lens it houses works beautifully but I almost never actually use it). It goes in whatever briefcase or shoulder bag I’m carrying, it’s always there when I want it and I’d never know it’s there when I don’t want it. Birdwatching, park- and city-scapes, architectural details, museum art from the back of the crowd: I use it all the time.
Regardless of which instrument, the real trick to these things is how one holds them. People grip them in two hands, front and rear like a stumpy telescope, or with one hand, like half a binocular. It’s pretty much impossible to be steady that way. Instead, make a loose thumb-and-forefinger ring with your strong hand (or the hand you use with your preferred eye), line your other fingers up with the forefinger, and hold that up to your eye like a kid pretending to look through a pirate spyglass (or think holding the neck of a beer bottle, but horizontal). Thumb makes a loose brace along your nose, forefinger about along your eyebrow. The monocular goes in the tube you’ve just made and is now being steadied by your head, with the hand just along for the ride. Focus with whichever finger falls naturally. You can hold with everything from a gentle pinch (you have to do that with the Leica while using the forward focus with your off hand) to something so loose the instrument is just resting there. It makes for a super-steady platform, even with the 10x Zeiss, and makes the monocular form greatly more functional.
Long first post but hope this is useful.