Carbon Copy Cloner which is free, or
SuperDuper which is not,
either will do a bang up job of cloning your OS X system, and it
will be bootable.
Keep in mind that cloning to another drive takes over the whole drive or partition, so this action will delete any existing data on the target drive or partition.
SuperDuper is my personal favorite, the almost instant replies to emails for assistance make the token payment well worth it.
Retrospect, yuk! the fact that they are trying to give it away should say something.
jb.