Mariah Carey has been a very busy lady during this last year of the millennium. Not only did she play a starring role in the upcoming film "All That Glitters" and pull down a smaller part in the movie "The Bachelor," she's currently working on renovating her new Manhattan loft and, reportedly, breaking in a new boyfriend. That's quite a heavy load, but amidst all that activity she also found time to record RAINBOW, a 1999 update of the slick, sumptuous R&B-pop found on 1997's BUTTERFLY that's sure to satisfy her worldwide web of avid fans. Some of Carey's new songs suggest that she's still getting her footing after parting with longtime songwriting partner Walter Afanasieff. But she makes up for the loss on a number of excellent collaborations with an array of major artists. Two versions of the tune "Heartbreaker" -- one with Jay-Z, the other opposite Missy Elliott and Da Brat -- show that Carey can step in the ring with hip-hop's toughest, as does the infectious "Crybaby," on which a thundering bass line underpins Snoop Dogg's flavorful flow. On the pop-R&B tip, Carey shares leads with Usher on the pleasantly bouncy "How Much" and with Joe and 98° on the ballad "Thank God I Found You." And if you crave Mariah up front and alone, she shines brightly working a tense, funky Timbaland beat on the up-tempo "Did I Do That?". She might not be breaking any new ground, but RAINBOW is a satisfying, at times scintillating, reminder that Mariah is simply one of the most reliable divas on the planet.