MSG should be avoided by persons on a low-sodium diet, including those with high blood pressure. So says the National Institutes for Health
This site, which is a bit more toward the outer edge of the envelope, has some interesting information about MSG: MSGTruth.org
But as I said before, I just don't see any point in the stuff. To me, it often alters the taste of particular foods, upsetting the balance in a recipe. I just don't care for the result, and I see no reason to add it to food. Others probably feel the same about salt or pepper.