There is little point in taking supplements if you don't already have nutrition really dialled in and are training intensely. Stuff like multivitamins and fish-oils have their place, but frankly anything more is just (expensively) convenient. Protein shakes are good if you don't have time for a REAL meal after training, but taking one instead of, say, some chicken, isn't going to magically put on muscle. Some supplements have their benefits, but it's just a very expensive way of trying to make up for shortcomings in your diet.
FWIW that promax thing is exactly what it says it is – a "substitute" for real food. And not a very good one at that.
Just my opinions, no doubt someone will disagree :P