You will be able to use it with Elite, it’s just “when” you’ll be able to use it.
You don’t necessarily have to get it now (I think current pre-orders have an ETA of June/July?).
I’ve heard people say that the Vive will be much more expensive too, but I wouldn’t put much stock in that until an actual price from Valve gets released.
I’ve got my Occulus on order, so I’ll just have to see how it goes.