what are the best protein shakes boost or ensure?

The best are the ones you make yourself at home from milk, liquid egg whites and whey protein powder (and flavorings you control). But if you're looking for quick and easy, then I like the nutrisystem ones because they're low in carbs. Look for ones that say "for diabetics" they're less carby and have higher protein. Walmart has a huge selection.

I really like Muscle Milk