According to the Amazon review it was inspired by their Live Aid performance in 1985 and subsequently released with two outtakes. Before you go out and buy/download it, remember that IT'S ONLY 4 SONGS.
The version of "Bad" on this is possibly one of my favorite songs ever. It's live and it absolutely rocks. It's impossible to turn it up loud enough. Trust me on this; it is one track that needs an 11. The other live track is similarly rockin', and the two studio tracks are both excellent. The recordings on the live tracks are very well done also, often a rarity. I think if I could ever see "Bad" performed live I could die happy immediately thereafter.
Which I guess virtually guarantees that I should never actually go see it if presented with the opportunity.
U2 is one of those rare bands that never really tails off in either popularity or quality, though I suppose Zooropa and Pop can be used persuasively to argue against the latter point (I certainly would). When they get away from the basics, I tend not to like it very much. For me, they reached a high point with Achtung Baby which, were it an old vinyl LP, would probably be worn smooth by now. Every stinking song on that album is good. I played it a lot in Egypt so it still brings back memories of, um, well, food poisoning and car accidents. But also wandering the Fayum, sipping papaya juice by the water, etc.
My first trip to Egypt is also made memorable by Pink Floyd's The Wall which I only really listened to for the first time while there. Weird. I also have REM's Green burned into my memory associated with the Metropolitan Hotel in Alexandria for some reason. Yes, back in the oooooold days, we were forced to spend 2-3 months in Egypt with nothing but whatever cassette tapes (CDs later) we could/would carry over. I would have absolutely killed for my 30 gig iPod back then.
UPDATE: Gotta admit, I'm listening to Pop at the moment and it's an excellent recording no matter what you think of the content. Everything is absolutely clear and the stereo separation makes the speakers seem to disappear. No matter what, those guys are perfectionists.