One of the things that seem to make a very little difference (if any at all) is spell checking. Is it useful?
Well, the answer is: Definately!
If the next command outputs a zero, then you don't need this feature
history| grep 'ks\|,ale\|male\|gi\|' | grep -v "history" | wc -l
Otherwise, keep reading.
For short commands you don't use tab, you can misspell them and zsh guesses what you meant.
Great, If you ask me.
rgrau@ares [ ~ ] %,ake
zsh: correct ',ake' to 'make' [nyae]? y
make: *** No targets specified and no makefile found. Stop.
rgrau@ares [ ~ ]:2 %ks
zsh: correct 'ks' to 'ls' [nyae]? n
zsh: command not found: ks
rgrau@ares [ ~ ]:127 %