I am soon getting the orchestral card for the Roland JV/XP series. I have heard many examples, and I say that if you are on a budget of some sort, that you purchase the roland synth. If you have about 7,000 dollars to spare--which I doubt you do--get a nice Kurzweil keyboard, because they use high quality samples.
*** - If you do decide to get a JV or XP series, dont rush into getting the orchestral card (unless you get an XP 30 which has it built in -- That's what I'm getting) because the Orchestral II card is coming out soon...the ROM sounds could be even better...