What are the ingredients of the MetRX protein shake you are adding the fruit to?If its just mainly protein you could buy better quality in bulk(say 5lbs.)much cheaper .If it has a lot of added carbs in the form of sugar you probably want to go with just protein as the fruit adds sugar and maybe add some raw oatmeal if you want complex carbs.As for the shakes generally just watch for the quailty of the added ingredients as you don't want a lot of refined sugars or hydrogenated oils etc. and you will be fine with them.You can always add various things to get pretty much any nutrient profile youwant and as you said it very convenient.Just watch the expense of heavily marketed individual package serving type products if you plan on frequent shakes.