optimum chocolate tastes like shit imo, with water at least. it's not bad with milk. i still use it since it's more cost effective than most. i figure i'm drinkin it for the protein not the taste.
for taste though, pro-rated chocolate was pretty good, especially with milk. sports one chocolate is decent, although my roomate just got a tub and his batch was really shitty, so i don't know what's up with that brand.
vpx micellean mrp's were good too (chocolate). haven't tried the straight protein though. biotest chocolate low carb grow was also pretty good, just doesn't mix well without a blender.
as you can tell i stick to chocolate flavors.