My wife bought this and loves it. She's bought others as gifts. It's easier for her than using the standard mouth to drink from. It does leak and I've accidentally tipped it over and learned the hard way. If you leave it sideways in a bag, on the bed, couch, or anywhere you will get a nice puddle. So I give it 4 stars. Also, curious if it effects the length of time that it keeps liquid cool/hot? My wife says her water doesn't stay cool as long and thinks it's a defective bottle, but I think it's the leaky lid since it's not sealed?? Maybe we need to do some science.