I gave this to my husband as one of my Christmas gifts instead of his other Shaker Bottle. I had high hopes, especially after watching the video of that guy mixing peanut butter in a milkshake. This cup really works! My husband has been using it to mix his Shakeology with other powdered beverage products. He said that it mixes well and is smooth. The only drawback so far is that it is smaller than his old vibrating cup, and it will not fuse if it is filled to the top (duh). To solve this problem, he filled it halfway, added powder, swirled the liquid to wet the powder, and then shook it to mix it well. After stirring, he will add more liquid and shake again (when we don’t spin and wet the powder, it tends to stick to the lid). He liked this cup of coffee very much, and he asked me to get another cup because everyone was using his coffee. This cup is really five stars. I only give the durability of 4 stars, because we only used it for 2 days, so it is hard to say now, but it is very strong, I hope to last for a while.