if you're like me an ride in loose dirt and cross streams then you'll like this bottle as it keeps the important spout nice and clean even after a messy downhill
i really like the high flow with minimum pressure that comes from this bottle.
Bottle size of the 21oz fits my frame better.
i like the cap as there isn't any grit regardless of where i ride.
These bottles are perfect for riding in muddy or wet conditions on dirt. They've increased the detent compared to the standard CamelBak bottles which makes it easier to grab while wearing (full finger) gloves, especially winter gloves. The cap does make it a little difficult to drink while riding, at least to get it back on when you're done, but that's a minor thing compared to the joy of not getting a mouth full of mud!
I like having a cap over the spout. I don't like that it takes 2 hands to open the spout or that water doesn't come out as a narrow stream. Biggest plus is that there are no leaks, so far.
I live in the desert in so cal so the trails get dusty. The cover on this cap works perfect and the wide opening on the bottle is great for adding mixes.