Flavorless (kind of, makes tap water "taste more like tap water" to me), but it has an insane glycemic index (higher than pure sugar, by some molecular miracle I've never investigated), which makes it great for replenishing energy while working out and terrible otherwise.

(Actually, on that note, I improved my jogging performance by 20-40% by adding 75 calories of maltodextrin immediately before starting, and completely eliminated the "I'm dead now" period afterwards with another 25 calories; I had a tub of the stuff left over from weightlifting, which since I've moved and haven't joined a new gym I'm not doing anymore.)