I think it depends on your views of management and unions.
The right-wing press will see it as a bashing for the union, and a climb-down, the left-wing press will see the union position as a pragmatic approach in a no-win situation.
I for one would hope this does not serve as a signal for any companies that they can force union agreement by simply refusing to keep a site open, which is not in the spirit of negotiation.
That said, it is hard to see this result as anything other than it appears - the union were told they could 'win', and loose 800 jobs, or compromise, and be seen as powerless in the face of the 'take-it-or-leave-it scenarion with which they were presented.
"Was this a victory for Ineos or for common sense?"
Vertainly not common sense - that concept has no place in this arena - it's down to the balance sheet bottom line - nothing else.