The default setting is for 4 desktops, arranged as a logical 2x2 grid.  Personally I set mine up for 9 desktops, so it's a 3x3 grid.  Other values result in similar, yet incomplete, grids. As most people do, I tend to use the same desktop #s for the same commonly used apps for consistency & ease of locating them.

When one-off switching to an app I tend to use the hotkey for the desktop #.  When I'm switching back and forth very rapidly between two (or sometimes 3) desktops, however, I tend to use the left/right arrow hotkeys.  I'd say arrow keys make up about 75-80% of my virtual desktop switches.  I think because of this, my mental picture of the entire set of virtual desktops is more like a horizontal straight line layout as opposed to the grid that it actually is.

Normally this doesn't even make much of a difference, but the recently added (and really nice) feature of slide out/in animations really made the difference apparent, and quite disorienting!  When I'm on desktop 2, for example, and I press the right arrow hotkey, the windows slide out to the left and new ones for desktop 3 slide in from the right.  But then I press the right arrow hotkey again and they end up sliding out up and to the right, and the new ones from from the bottom left corner because desktop 4 is on the next row of the grid.

I haven't tried it, but I think the same thing would happen if you were to go up/down off the top/bottom.  Say from desktop 5 to 2 by pressing up, which makes the windows slide down (expected), but then going "up" again leads to 8, which is actually "below" 2, so the windows will slide up (not expected).

I wonder if it would make sense (and/or how difficult it would be) for the animation to consider arrow hotkeys, and override the window sliding direction to be consistent with arrow hotkeys?

Going direct to a specific # could still behave as it does now, or even better have a separate animate windows toggle for each of the two hotkey navigation modes!  Personally I'd turn off animation for direct jumps (an "absolute" location change/teleport) and on for arrows (a "relative" movement).

What do you guys think about this?