Emu XL-7 & MP-7 User's Group

Hi there, just purchased a Command Station and have a question about
additional Rom. 
For example, if I purchased the Beat Garden rom, it gives me
additional presets and the instruments used to make them? Is that
right a rom gives you presets and instruments?
Or is the list of instruments that came with the original ROM all that
you get to work with?
What additional Roms to people find most useful in the command station?
Thanks