: Hey Blair!
I have the Platypus Gravity Works 4.0L and the Sawyer Squeeze, and have a lot of experience with using just chemical treatment as well so hopefully, this answer helps you!
I LOVE The Platypus Gravity when I'm running groups. I can set and basically forget it and its easy for group members to grab what they need. It falters a little when water sources are low as filling the "dirty" bag works best from a moving water source (stream, brook etc), or something like a lake.
The backflush is easy to use while backcountry and you don't need an extra tool along for it which is nice.
That being said - Its a lot for one person. I'd recommend this product for groups of 4+.
If you're going alone, or 3 and under, a Sawyer will work just as well.
If you're hiking alone the Platypus is a bit bulky. Also not great for cold weather.
Let me now if you have any further questions?