We have two of the 20oz container cups and are used extensively between my husband and myself. I love the double wall, no cold hands/ warm smoothies! The bottom of the cup is the perfect size for the car cup holder. We have never had problems with leaking around the base or the sip top. Even if the cup sits for several hours after a smoothie, if the lid stays locked it doesn't get crusty and is very easy to clean. I also like that its 20 oz, can go smaller if wanting less, but gives the option for a "share size."