SQL TEXT information?

Could someone please post some information about Oracle SQL TEXT?

Is it a serious text retrieval product? Are its text retrieval capabilities well integrated with the rest of the Oracle toolset? Are text retrieval queries specified with SQL, or with some sort of proprietary text retrieval extensions to SQL? Is there a large overhead when inserting text records into the database? How much space do the text indexes use, 50%,100% of the data? Is it fast?

Thank you for any answers to any of these questions.

     ___      :  Philip Anderson, Hypermedia Group,
    /___\     :  Collaborative Information Techonology Research Institute
   //   \\    :  723 Swanston Street Carlton Victoria 3053 Australia
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 /_____//__\  :  Phone:    +61-3-282-2496
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\\___/\\___// :  E-mail:   phil_at_kbs.citri.edu.au
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