I have mixed views about Ambrose myself. He's a talented writer, no doubt, but there's always the concern of what's actually his and what's not. Also, his books tend to be incredibly Amerocentric. As much as I liked D-Day, the US Army/Navy are very much front and center.

Atkinson is very much in the old style of military history. His books tend to be very detailed, almost to the point of absurdity. He does miss the forest for the trees a fair bit of the time. But, if you're interested in extremely detailed work, he's a good author to read. Again, his books are explicitly about the US Army, and the US Army in the European theater at that.

Beevor I haven't read a lot of, but his work is generally good, at least what I've read of it. He's a very engaging writer. Mercifully, he focuses much more on the Commonwealth experience. As an American, that's something we don't get a lot of.

Hastings' work has a range. From what I've read of it, it's engaging and doesn't make any real egregious factual errors.

One of the larger issues is that a lot of the popular literature focuses almost disproportionately on Europe, particularly Western Europe and the Commonwealth/US forces. Italy/Sicily/North Africa tend not to appear too often, though Atkinson's work is obviously the exception.

I know Cornelius Ryan is much less frequently read today than he was some 40 years ago, but The Longest Day and A Bridge Too Far remain excellent.

I'm not really sure what you mean by "very popular." The curse of reading so many books about WW2 is that there are some authors who write one or two phenomenal books, then disappear into other things.