NYT story here. I have not had an opportunity to read the opinion, but there is a link to it in the article. My impression is that the executive order is most vulnerable on religious discrimination grounds, given the ordinarily wide latitude given to the executive branch in immigration matters (though not as wide as the government lawyers are trying to argue). I am pleased on the moral merits that the courts are pushing back against the Idiot-in-Chief, but the ultimate legal merits are trickier here. I'm quite sure Trump has not helped himself with the judiciary by his initial responses, and that may yet carry over to the Supreme Court, which will get this case next. The religious discrimination argument could, in fact, persuade some of the more conservative Justices--and add to that the fact that they may also feel the need to make clear that the Idiot-in-Chief can not do whatever he wants.
UPDATE: This is a more nuanced discussion from one of my law colleagues who actually read the opinion!