If you can just have the one then I'd recommend the first orchestral board. I own the first, and had a play with the 2nd in a music shop and whilst it's very good it seems as if it was designed to supplement the first board. Many of the patch names carry on from the first, e.g. Orch II has patches 'Oboe 5' thru 'Oboe 8' - 1 thru 4 are on the first board.
Orch II also seems to be missing several key areas that were coverd extensively in the Orch I board, mainly in the percussion department, though the second board has much more in the way of Pianos & Choirs than the first (+ the extra Celtic stuff, think Riverdance). Seeing as the JV1010 has the session board, you should be doing OK for choirs / pianos anyway...
At the end of the day it is probably best if you hear both boards yourself, but IMHO if you can only have one then go for the first Orch board.
Good luck!
Pete