QUOTE(Viledin4u @ Apr 24 2012, 01:57 PM)
Are the standards similar?
Yes, the standards are the same.
Teachers tend to have a preference for one or the other, or choose which to use depending on the student. You can find examples of the same pieces being set at different grades by different boards, but that doesn't mean the exam is easier or more difficult as a result, just that they're looking for different things. To put it another way, something such as the Debussy violin sonata, on the ABRSM Grade 8 list, could just as easily be a diploma piece, or be used in a recital at music college.
All the information about exactly what's involved is available from the boards' websites, although it tend to be spread over several downloads, with aural tests for example being separate from instrumental syllabuses.