This depends on many factors such as
the translation program, the type of translation, the grammar of the
document to be translated, the use of a specialty dictionary or glossary,
among other factors. The quality of the engine of the translation program
and the size of its dictionary are usually the most important factors.
Generally, you can expect draft-quality translations: the result can be
readily understood, but will need editing and correction for professional
use. Again, a professional translator or firm should be used for demanding
or mission-critical applications such as legal or literary work.