I suggest that you stick with ON Gold Standard, and stay away from Muscle Milk. ON Nutrition is 24 grams protein at between 110-130 calories a serving (one scoop), depending on what flavor you get. Meanwhile Muscle Milk is 35 g protein and 300 calories, but that is a two scoop serving. Also muscle milk is a protein mixture where as ON Gold standard is whey only.
Reasons to not use Muscle Milk:
1) Itís a blend of protein and other substances that help body builders more then other athletes, 300 calories are a lot.
2) For athletes anymore then 30 grams of protein at a time for non-bodybuilders is usually overkill, if you really want to use muscle milk you could first try just using half a serving. (1 scoop)
3) One ingredient in Muscle Milk (glycocyamine) has been tied in with increasing homocysteine levels, which is a marker for cardiovascular disease.
Mixing in Water vs. Milk:
Post workout I would suggest immediately after your last lift drinking your whey with water and maybe having a banana as well. When mixing with water there is faster absorption into the body while milk causes slower absorption times. Mixing with milk at other times of the day for slower absorption is ideal in various situations.
Whey and Casein Protein:
Although not in the original post there seems to be some misconception on this through out the topic. Whey protein is ideal for pre, intra, and post workout. If you taking protein during any of these times, itís the fastest absorbing protein possible, making it ideal for these times of exercise when your muscles need protein the most. Casein is a much slower digesting protein; this is because it takes the body much longer to break the proteins down vs whey. Casein is usually taken before bed to help with muscle recovery while you sleep, as it will work longer into the night. If interested in taking a Casein supplement I would suggest Optimum 100% Casein Protein. Just note that is a much denser powder and when you shake up pure Casein protein supplements it becomes more of a sludge/yogurt type consistency.