Turns out this is a pretty good cover. Worth of SOTD, in fact.
The original version of "Nothing Compares 2 U" was written by Prince and performed by his early band The Family. But, it rose to fame when SinÃ©ad O'Connor picked it up 1990. I'll confess that I don't think I'd ever heard her version until I checked it out on YouTube today. Personally, I think I prefer Capital Cities' rendition.
Quoting the band:
Working on covers is a sacred exercise for Capital Cities. We meticulously pick songs that we love and then explore them until new harmonic and rhythmic ideas emerge, hopefully bringing a freshness to a timeless melody and lyric. It's an exciting process that always leaves us in awe of how brilliant our musical predecessors were.