mine were defective
I'm an adult mom who bought four of these for our family. The vents didn't work and they leaked- every one of them. We returned them. I wish I had read the reviews...

Works great, doesn't leak for me, kids love 'em
You can order alternative caps like the other Sports Cap on Amazon by New Wave, or you can order other kinds of caps (and a bottle cooler/carrier) from their website directly (free ship on orders over $8). By the way, if you want to fill it with a fizzy drink, these spout caps don't hold up to the gas pressure. Order a spout-less cap.

The caps are easy to sip from for my 4 year old, who can also pull open and push closed the spout without adult assistance (this is nice because his preschool teacher might not check on how well the bottle is closed for him--ie, stinky milk mess in the lunchbox at the end of the day.) This cap is easy for him to handle alone.

You can also just unscrew the cap & pour or drink from the bottle directly, if you want to.

The steel wall itself seems sturdy enough, easy to clean with my bottle brush, & the steel bottle isn't too heavy for my 4 year old to hold & sip from.

leaky cap!
I wish I had seen that warning about the leakiness before I bought mine! It leaked water in my bag and fried my cellphone. Needless to say, I am extremely unhappy at this point as I need to go buy a new phone tomorrow unless the air conditioner manages to suck the moisture out of the non-functioning keypad. This cap stinks! It is a slow leak, so if you are just throwing it in a gym bag or beach bag, I guess it's OK, but don't put it in any bag with anything that needs to stay dry.

nice product
This is a nice little water bottle. It is made of thinner stainless steel than the Kleen Kanteen bottles, so it is lighter, but may be slightly less durable. The lids are interchangle with the Kleen Kanteen lids.

Good Price but Leaks
I bought this for my son because of the low price. From day one it leaks out of the air hole on the top. I'm contacting the company as I doubt this is supposed to happen. Hope it is resolved.