THE DEFINITIVE GROOVE COLLECTION may be a little too much Sister Sledge for casual fans, but for deep soul/disco lovers, this collection is a must. Besides the expected hits, this anthology includes such popular album cuts as "Betcha Say That To All The Girls" (featuring a humorous rap by jazz singer Al Jarreau), "Super Bad Sisters" (one of the earliest rap/sung collaborations), and the creamy Phiily disco/soul of "Pain Reliever". It also includes three non-album singles (The Top 20 UK hit "Mama Never Told Me", the ballad "Thank You For Today" and the peppy "Cream Of The Crop", which crawled to #100 on the Billboard r&b charts in 1976). The usual quality Rhino liner notes are here as well as clean remastered sound. According to the liner notes, Sister Sledge gets a mechanical royalty whenever "We Are Family" is played although they didn't write the song.