[wwarek]

Switching from Chrome the most annoying thing in FF was lack of tab switching with Ctrl+<number>. Fortunately there are extensions providing that. Works great for 5-6 tabs, especially when it gets into muscle memory (not sure if that's correct term in this case but what I mean is that brain "knows" that ctrl+1 will be X and Ctrl+3 will be Y and can switch between tabs without thinking of their actual numbers)

[m6w6]

It's ALT+N

[klyrs]

And if you're a tab-hoarder,

   alt+1
   ctrl+shift+tab

Goes to the rightmost tab