From the type of material to the style of the cap, the best water bottles can be customized to suit your specific needs. Vacuum insulated stainless steel is almost unbeatable when it comes to keeping cool, but it is prone to denting if dropped and can leave a metallic taste. Plastic—look for BPA free —is lightweight, sturdy, inexpensive, and easy to clean, which is why it’s a go-to pick for athletes instead of glass bottles. But it’s not insulated and can give off-flavors and smells. Glass water bottles don't transmit off-tastes or odors (and may appeal to aesthetes), but it’s definitely heavier, costlier, and more fragile, making it less than ideal when it comes to portability/durability. You’ll also want to consider quick access versus screw caps. Push/pull designs can be simply flicked up with one hand, and actually provide some sort of straw or spout lid to drink from. The other type needs to be actively undone with two hands, but is less prone to breaking, and is easier to disinfect and clean.