Very well designed...
Easy to use with one hand.
Sealing cap that keeps the mouth clean.
Easy to fill, easy to rinse, fits electrolyte packages, sachets, or tablets easily.
Good quality plastic, no signs of wear after extensive use.
UPDATE after about 2 years of use. All the above still applies, however, when I used it for electrolytes for a period of time, the smell remained for months despite washing it with detergent, etc. Eventually, it disappeared. Perhaps an expected drawback for a plastic bottle.