You will likely get up and going more quickly on skis than boarding, however as others have said it takes longer to get to intermediate level and competance off piste will likely take a long time. Plus point with skis is that getting round the mountain is so much easier than with a board, you can cover flat ground much more easily, which is a killer when you first start boarding.
Now for boarding, as others have said the feeling of being off piste in deep powder snow, in the trees or on steep open slopes has on occasions for me been almost a spiritual experience :0)
So try both they are both great in there own ways and for different conditions.