How can I switch spaces instantly?
I recommend the option System Preferences > Accessibility > Display > Reduce motion. 

This causes the transition to become a simple fade, which is also much quicker than the screen pan especially when using ctrl+1, 2 etc shortcuts.

I also use this option on iOS for similar reasons.


There's also TotalSpaces2 which apparently allows complete removal of the transition. I've not used it myself though.