Looks like an embargo was lifted as we have a bunch of reviews from the UK coming in. This one from Autocar.

>It feels properly rapid รขโ‚ฌโ€œ the turbo spools up with almost no lag and the engineรขโ‚ฌโ„ขs strong mid-range makes for effortless urge in any gear. Passers by get to enjoy a rorty exhaust note, into which some over-run รขโ‚ฌหœcrackleรขโ‚ฌโ„ข has been carefully engineered. But, unfortunately, inside the cabin it sounds flat and insipid.

And this was interesting.

>The most surprising thing about the John Cooper Works is just how much equipment it doesnรขโ‚ฌโ„ขt get รขโ‚ฌโ€œ and which has been reserved for the options list. Despite a pricetag that puts it into direct contention with a 2.0 TFSI Volkswagen Scirocco, the JCW makes do with same standard, unsupportive seats fitted to the standard Mini Cooper. Proper buckets are a pricey option.

Great review with even more to come.

[ Mini John Cooper Works ] Autocar.co.uk