How long are you planning to live on protein shakes for? How long do you think you could go without physically eating something substantial? (other than nuts etc.) I'd personally rather eat real food...get your nutrients that you need from real carbs, proteins & fats...you can't beat the real thing...Your body need to have texture to feel siated...the crunch of an apple, be able to chew a steak etc...a shake for a pwo meal or if you are pressed for time is appropriate, but as for Herbalife, I *think* shakes are 80% of nutrition throughout the day (maybe I'm wrong...not sure). I would be careful...even if you need to drop an assload of fat, I would be wary about taking on something that offers liquid as the main part of the diet and go for a consistant 40/40/20 split instead.
Have you thought of what you will do to add food in after you are on these meal replacement shakes when you reach your goal weight? Most probably, your body will react to real food and you will start all over again as your weight will go up quickly, especially if you are eating the wrong sort of foods.
What are you eating at the moment? What exercise are you doing in addition to your eating habits?