There are a couple different ways U2 remixes go. There are the literal ones, that just rearrange the levels and tracks from the original mix (like the Mike Hedges mixes on Best of 90-00, or the USA versions of Two Hearts or New Years Day). There are the ones that create a completely new backing track. There are ones that sample from the original song and combine with varying amounts of original tracks. In general, they cover a wide range from just barely changing the song, to adding a dancy rhythm, to creating a new feel, to creating an entirely new song.
I'm a huge fan of the remixes. My latest thing has been buying vinyls with exclusive remixes, copying them to my computer and cleaning them up. My current favorite is the City of Blinding Lights - Phones P.D.A. in N.Y.C. Mix.
I gave a listen to the Pete Tong Exclusive radio rip of the Crookers mix. It falls short, but I give credit for the attempt. They had an interesting take on the song, it strips down the original quite a bit. I think it could benefit from a stronger rhythm throughout, especially during the verses. Not good enough to buy on its own, but perhaps if it backs one of the singles.
I'm actually just starting a big U2 remix project of my own, though my options are pretty limited with only the full versions of songs and not the studio recording tracks.