Has anyone read it? It came out about 10 years ago, and while I've never owned the issues, they're all on youtube, so anyone who wants to read it is available to. In my opinion, it was a great crossover event that delivered everything it promised and certainly paid respect to each Universe.
Highlights for me were:
Superman and Captain America taking jabs at one another's reality, and almost fighting at one point
Batman taking down the Punisher when he's supposed to be doing something else ("I hate drug dealers, but I hate what this guy's doing even more." Or something like that lol)
The epic battle at the End
Superman wielding Mjolnir and Cap's shield
Batman taking on Batroc the Leaper and some of the top fighters in the Marvel U.
The scenes where reality keeps getting shifted
It's mostly just satisfying to see the characters from the 2 Worlds interact. In the past when they've done crossovers, it's usually been all about seeing 2 characters together, but this crossover was really great for respecting the 2 Worlds.
Link to the first issue: http://www.youtube.com/watch?v=BHW5X9fjJKQ