Hold on Dr. Warbird, j/k, 1000mg of r-ala might be a little wasteful. I thought the general consent around here was 1g carb = 3mg R-ala. So 200 carbs a day = 600mg R-ala. Even if you don't consume 200g carbs i would stick to at least 500mg a day.
AS for which do you buy, tell us your situation. How old you are, how much you weigh, how important money is, do you mind side affects, fill us in.