I saw this on tap last week and tried it. As a fan (I would like to think "connoisseur", but it's up for debate) of IPAs, I had the following reaction:
It is surely nice and bitter. I don't doubt that it has 1000 IBUs, even though the human palate has diminishing returns beyond 100 or so (no sources, just what I have heard here and there so take it with a grain of salt).
But IBU does not a great beer make. It has very little else going on besides bitterness. No distinct aroma to speak of. No distinct hop flavor to speak of. No distinct malt flavor to speak of. It just tastes like a carbonated bitter-water with alcohol.
I respect Mikkeller and I would like to think they made this beer as an ironic statement against "extreme beer" - that IBUs are not something to be proud of; you can't measure a beer's flavor by some quantitative chemical benchmark. IOW, I suspect they are IRL-trolling the "extreme beer" crowd, just to see what the reaction would be.
If you had this beer, please post your reaction (no judgement if you liked it, seriously). If you didn't have this beer, post your reaction to the idea of it.