Overall I like this lid enough to keep using it. Just wish it didn't leak when closed and on its side. I think it leaks because a bit of water gets trapped under the part that twists. I'm not sure how to prevent that, from a design perspective.

I trust the Hydro Flask brand. I won't buy off-brand lids. I'm worried about off-brand black plastic lids for Hydros that I find on Amazon. . . . a lot of cheap black plastic can contain toxic flame retardants from recycled electronics, so I don't want to buy any off-brand black plastic lids. Those manufacturers don't even say whether their lids are made from post-consumer content or not, so I worry the chances of those lids being made recycled electronics could be fairly high.

I trust Hydro Flask when they say they don't use recycled plastic because they've yet to find recycled black plastic that meets their high safety standards. I only want to buy HF-brand lids for this reason. But man, we need some better lids! Please put more effort into your designs.

I've been a loyal Hydro Flask customer for over ten years. I have many HF products. This is my feedback.

*Don't buy this if you're a hiker, it's so heavy.
*There are 4! (Four)! pieces to be disassembled, cleaned, dried, and then reassembled.
*If you use it to drink anything other than water, you must clean it right away. Never leave it till later, because residue from the beverage will dry in aaaaallllll the crevices and indentations, and you'll need to use toothpicks or q-tips to get it out. And that stuff, if not completely removed, will cause odor and mildew that is impossible to get rid of. So, if you buy this, be prepared to completely disassemble and clean it every night.
*The four part cap must be put back together in precisely one way. Otherwise it will leak with every sip.
*Be careful when twisting the sip lid. You may turn it slightly too far and begin to unscrew the main cap, which causes spills.
*You need both hands to get it open to take a sip.

I'm anxiously waiting for the company to design a new lid that is lighter and has fewer moving parts. Until then I'm using my Contigo. I just push a little tab and pop! it opens one-handed!

I love having a handle on the lid. And before I used to get a spot of coffee on my nose if I lifted the cup too close to my face when drinking but that isn’t a feature in the new lid. But I hate the new “flex lid”. I’m on my third lid of this type. I have to take apart and reassemble 4 pieces every day now. I used to just toss the old one in the dishwasher. This one has such small pieces that they require special care to make sure they don’t end up on the heating element of the washer. The time it takes to clean is exponentially more. I could maybe get over that but it also leaks. And when it leaks it doesn’t come out of the top - it comes out of the sides and drips down my chest while I drink. I have stained two shirts already. That silicone seal gets twisted when you close the top and eventually fails. It’s infuriating. I bought a different brand. The HydroPEAK cup doesn’t stay as hot but at least it doesn’t steal my time and ruin my clothes.

I was very pleased with customer service, as they have always been quick to replace lost or broken parts. In this case a recently broken old style cap broke, and a new model was sent free of charge, 5 star service, thank you.
However the new wide mouth flex sip design caused hot liquid to come in contact with my upper lip sufficient to cause a burn!!! The new design is way too complicated as well. It has 4 parts, a top, a silicone gasket, a bottom and an inside part that fastens to the top part. What a pain to disassemble to wash, let set out to dry reassemble an hour or so later and put away for the next day!!!! Why a company that makes a terrific coffee mug gave up on a wonderfully simple 2 part top that snap hinged closed was way easier to wash, with no disassembly, and never burned my upper lip, is unbelievable! 0 stars for the engineering of the new wide mouth lid!