It all depends upon the individual. For instance, I have a diabetic elderly friend who hates just about all meat, and didn't get enough protein in her diet at all. I introduced them to her as a last resort, as I didn't think she would like them (she has to be one of the pickiest eaters I know, and if it's good for her, she hates it, lol). Turns out, she loves them. I got her the low carb, high protein shakes, and it really helps her balance out her sugars, and meanwhile, she is getting the protein her body missed all those years from poor dieting.
My best friend, who had introduced me to the friend I just talked about above, tried one of her shakes, and drinks one every morning with two pieces of fruit. She loves it, because it is a fast and easy breakfast, and it fills her up until lunch time.
For me, they do absolutely nothing. I get hungry within the hour, even if I have fruit or veggies with it. I get hungry with just the protein shakes alone. Even the low carb versions do not fill me up at all, I have to have something solid in my body for my first meal of the day. I usually have a veggie omelet made with egg whites and low cal cheese and two pieces of whole grain toast with coffee. That fills me up for a long time. So, shakes are not for me, but two of my friends love them and can't say enough about them. It's all up to the individual and whether or not they are satisfied by them. Try them out, it can't hurt to try, right?
Oh, and yes, both ladies are losing weight off of them, in case you are wondering. They are a great tool for the both of them, so I am glad that I introduced it to the two of them, at least the shakes work for them.