I’m genuinely interested to know what is your workflow so that TotalSpace has become a requirement overtime?
Today I learned to do without because I couldn’t convince myself to use a half-working product…
For me, I needed TS for the 3d grid so that I could memorize “where on the grid” are some window or apps so that I could use space memory to get there easily.
What is your need for TS / your workflow with it?
Very similar to you.
Spatial cognition is one of the oldest, deepest and thus “fastest” and energy-efficient cognitive systems we have. Pattern recognition if more so: it is at the very base of our neurocognitive abilities.
I have ADHD, which means, among other things, I have very limited active memory. So I need, for example, to keep everything related to a task/project open and available to my eyes to see. I use all 16 Spaces, and access them via quick spatial survey (the 4x4 Spaces overview grid) and pattern recognition.
i.e.: I use the Expose hot corner (top right) to quickly (thoughtlessly, this is important) to invoke the grid and visually recognize the pattern of an open set of apps etc in a Space to dive into it with a click.
Right now I am using Mission Control to do this, but the long one-row strip does not allow as simple spatial reference (16 positions is too much, 4x4 breaks it down into cognitively manageable pattern); and it makes the previews too small to quickly recognize. So essentially, it does not really work for me. I get overwhelmed every single time, and my work is suffering for it.
For me, it’s mainly about invoking the overview grid with an instinctual gesture and using pattern recognition and spacial cognition to quickly recognize a context and dive into it. The absolute key is minimal minimal minimal cognitive overhead to context switch.
p.s.: I am a researcher at a Japanese technical university working on “UX for Neurodiversity”, so yeah this is something I think a lot (too much?) about. 
My main beef with Mission Control is the fact that I cannot see the content of the spaces properly. I end up with many similar windows with different content, and I kind of associate the contents of the window to the task I am working on. Looking at them in Spaces/TotalSpaces is easy and quick to switch context.
I use hot corners to manipulate my space. So a wave with the mouse or a flick at the trackpad is enough for me to see things and a single click gets me where I want to.
Mission Control is much more clumsy because I need to click on each space separately to find what I want, because everything is too small. Everything while while some key down so it stays on.
So what I can’t do without TotalSpaces is to work quickly and without silly distractions. Which compounds to a lot by the end of the day.
It enables me to handle interruptions and multiple tasks.
I lay out everything for one task horizontally like mission control wants me to but often I will have to switch between tasks. This is what the vertical aspect allows me to do. I can use spacial cognition to organize various tasks in various states. All it costs to switch is the time it takes to shift my thinking and move around the grid. Everything stays where I left it.
I have multiple monitors and the ability to have virtual desktops which solves most of the same problems that windows do. For me one desktop = one window. I don’t have to click anything and I can organize my work in a way that makes sense to me.