When word completion is enabled, and the initial few characters of a word
(present in the word list) are entered, a completion is presented.
When there is more than one completion, and the presented one is not the
one wanted, the user can either reject completions at all, and complete
himself the word, or enter ctrl-tab to cycle thru completions. In this case
word completion is almost useless since the number of ctrl-tab's to be
entered and the pain to hit two keys simultaneously is most of the times
higher than completing the word.
In my everyday experience at least half of the words have more than one
completion. This means that a very useful feature fails to provide its benefits
half of the times.
This could be overcome by displaying the completions one each second, having the
enter key (or the configured one) accept the dispayed one. Alternatively,
a popup could be displayed showing all completions and letting the user click
on the desired one, but this makes the user move a hand from the console to the
mouse.

-Angelo Borsotti