This little bit from the Los Angeles Times is a good intro:
“UNDERRATED: 'Only Lovers Left Alive' (2014) With the genre feeling drained after "The Strain," the "Twilight" series and the just-departed "True Blood" (to name a few), leave it to Jim Jarmusch to find a way to make the blood-sucking myth feel new. Centered on the relationship between Tilda Swinton's character (wonderfully bizarre as usual) and her depressively reclusive partner (played by Tom Hiddleston), Jarmusch's deceptively tender love story thrives in a world that may be too dark for vampires.”