truncate table

Hello.  We have an inquiry with respect to the truncate table command.  Is it the case that the truncate table command should execute reasonably quickly regardless of the number of rows in the table?  We've learned that using the Drop table command on a table with a large number of extents will take a long time and we found a Metalink Note with steps on on how to drop table a table with a large number of extents.   But, we're wondering about the truncate table command in that we want to avoid a situation wherebby we execute the truncate table command