I bloody love this flask.
Firstly, it doesnt leak - you can throw it around, turn it upside down. It's got a great seal.
Secondly, it has a great lid with two simple steps to take apart and clean. This seems a robust and hard wearing mechanism, that's simple.
(I bought another brand prior, and took it apart, leaked ever since - this does not!)
Thirdly, last night at just before 10pm i made a cup of tea in it as I am staying away from home.
Fell asleep before I'd even made a start on it and at 8.15am this morning it was still hot!
And finally, it feels nice to hold, slight texture on the sleeve makes it easy to hold and not slippery (I drop things a lot!)
Absolutely worth the price!!
Also I would like to mention how great Sea and Stream are with delivery and returns as I have used them for several items.