I've bought 2 of these (plus a bonus one I got in a surprise goodie bag), and I love them so much. They are sturdy and so pretty, and I love seeing how much water I have left because it motivates me to keep hydrating. I will say that if you drop it, even from ~6-8 inches onto a carpeted floor, it's very likely that some part of the cup will crack. My first one I dropped and it broke in two pieces...but I wrote CWM about it and they sent me a replacement which was SO KIND!! The second one I dropped only cracked slightly on the top inner wall part, so while I could still drink out of it, water began to leak into the part between the two "walls" when I filled it too full or tilted it while full, so after awhile I worried that it would start to grow mold or something inside there. Thankfully I still have TWO working ones since I got the bonus one in that goodie bag!
I guess the moral of this review is: if you're not as clumsy as I am, you will 100% love these cups. If you lean on the klutzy side, beware that they may not last you as long as you'd like. (Still 5 stars for cuteness, functionality, and amazing CWM customer service as always!)