I bought this tumbler mostly to reduce single use cup waste and liked the added bonus of it keeping my iced latte cold throughout my shifts in a pretty warm environment. It does both very well! I think it says not to run it through the dishwasher but at that price I decided to risk it and so far have had no issues. I haven’t knocked it over so can’t say how leak proof it would be under those circumstances, but if used as intended there are no issues with leaking.I use this every single day. It keeps my cold drinks cold forever and I can put almost everything I drink in it except hot drinks. I love it though.The cup itself is great quality - sturdy, easy to clean, and the shimmer looks really nice.Unfortunately, the lid that came with the cup has a slider piece that is permanently affixed to it with two plastic brackets, making it impossible to clean. Over the course of several months (despite hand washing, soaking overnight and numerous runs through the dishwasher) the gap between the slider and lid began to develop a thin layer of mold.It’s still a great travel mug for the price, but I do recommend purchasing the following lids, as they fit snugly to this mug and allow for much easier cleaning:20 oz Tumbler Lids, Fits for 20... https://www.amazon.com/dp/B0821MDL9D?ref=ppx_pop_mob_ap_shareI haven’t tried the cup for anything hot yet but it keeps my iced coffee cold for hours. I love this cup!I work in a hot warehouse so drinks get hot fast. I put ice in my cup from home around 9pm when I get off work at 6am there is still ice in my cup. I love this cup. And it’s cute.Love this cup. It was supposed to be a gift but I ended up keeping it. Leak proof as far as I've seen. Super easy to cleanThe cup is perfect for the purpose I purchased it for; keeping fresh, cool water on my desk at work, while minimizing the risk of spilling it on myself or my work (e.g. paperwork, phones, and computer keyboard).It keeps the water nice and cool throughout the work day, the straw is perfect for drinking while keeping the cup upright, and the design minimizes the risk of spillage if I were to knock the cup over.It also looks attractive on my desk while not being eye-catching; important because I'm at the "front desk" and appearance to clients matters.However, because it DOES use a straw, I wouldn't personally choose it for drinking anything containing sugar (natural or otherwise) - e.g. fruit juice, soda, or sports drinks - and/or particles that could cling.The straw is wide enough to easily be rinsed out at the sink, but if I weren't able to immediately rinse, and/or consumed the drink over the course of a day, residue would be difficult to remove.I love this tumbler I use it nearly everydayGreat for anythingHowever the lid gets grimy after a while if using with coffee