Doesn't taste of much. Best to add flavour such as chocolate powder/vanilla/almond essence.
Maybe I've misunderstood, but all protein powders should be gluten-free (except perhaps for disclaimers about traces), unless they're full of strange 'valued-added' products.
Yeah, traces definitely matter. My girlfriend is a coeliac and suffers terribly with contaminated food, although she regularly uses MP products without trouble.
If you continue having problems, skimmed milk is spot on... will also contain less fat and carbs... (add carbs as you wish, i.e. a banana, some choc powder...)