I've tried a few different shakes, both powered and premixed

the first kind i tried were carb solutions vanilla premixed .. they were rather disgusting on their own, and then i discovered that i could put them in the blender and 'doctor them up' to suit my tastes, after that they were decent

after that, i got carbolite egg protein powder, chocolate flavor, and it was excellent .. unfortunately, the place that i got it [netrition] i just found out is no longer carrying the egg protein kind

more recently, i bought both vanilla and chocolate flavors of the atkins shake mix ... neither are all that great as a drink, and the vanilla is particularly bad; however, there was something on the side of the can that said to mix 1 scoop with 1/2 cup cream and a packet of sweetener and whip that up [easiest in a bowl], which is declicious with the chocolate, but again, not that great with the vanilla

i also, at some point, bought some of the coffee flavored carb solutions premixed drinks (saw them at walmart, figured i would try) .. they're a lot better than the vanilla, but i've found that putting them in the blender along with some cream, additional sweetener, ice, and a little bit of the chocolate atkins mix is much better than straight out of the can