USN Ultra lean diet Fuel.
I use it, and wouldn't be without it because it's a filler on those wonderful metformin filled days when I feel sick as a dog and can't face breakfast. However, it tastes just as sickly sweet as all other meal replacement drinks that I've tried. I buy the vanilla one off ebay so that I can doctor it with cocoa, or frozen berries, or whatever else I have on hand to make it more pleasant.
I have friends and family who like it and think that it tastes like melted ice-cream. So maybe I'm just taste impaired (I hated milkshakes as a kid).