I use this for my drinks in the morning and after work outs. I have read that they leak. All you need to do is make sure your lid is own tight and if you stop it and add something make sure your lid is tight.
I received this as a birthday present from my fiancée earlier this year. Since then we have used it at least weekly to create smoothies before work, and have also used it to makes sauces for cooking. We've never had any problems with it, and it is very easy to use, clean, and maintain.
I had already used the NutiBullet for a year. I upgraded to NutriBullet PRO and have been very satisfied. My only problem is getting the rubber sealers to stay in place.
I have used my NutriBullet for over a year now and absolutely love it. It works great for making smoothies, mixing and chopping kale, frozen blueberries, ice cubes and just about any fruit or vegetable to a creamy smoothie. My only complaint is that the plastic container is a bit hard to keep clean. I wash by hand and because plastic is porous, it seems to smell like fermented fruit when it sits between uses. I have to re-wash before each use. It would have been a better product if the container was made of glass as it would have solved this issue. Other than this minor problem it is an excellent product.
I use my NutriBullet 900 Series every morning for my protein shake (with ice cubes). It works in less than a minute then I screw on the handle and enjoy. Cleanup is fast and easy and I use the included extra cups with lids to carry other drinks with me in the car. LOVE it! p.s. I just bought the milling blade to make my own almond flour and almond butter but haven't used it yet.