I've been blending my morning green smoothie every morning for several months now using this container. Love that I can blend and go. I've had no problems with leaks. On the down side - it is bulky but I'm sure the double sided insulation is needed to keep drinks cold. The lid has too many nooks that make it not so easy to clean. The sipper opening on the lid is really tight and difficult to open. However, I'd rather deal with that than have leaks as others have complained about. People have remarked that the cup is huge but I don't think it's too big for blending a smoothie and using for other blending. Overall I'm happy.