Dishwasher-safe. Easy to clean and fill. Cap closes securely and flips out of the way for comfortable drinking. Better drinking ergonomics and less complicated than many others (not a fan of needing to fuss with straws that need to be removed and cleaned).
I do love the larger, 32-ounce Nalgene (the classic Nalgene bottle), but I got this in order to have a bottle that fits in standard cup holders (including the bottle slot in my shoulder bag).