I like Platypus and have several though since they aren't 100% compatible with the Sawyer-Mini filter (screwing directly on the Platy) I switched over to Evernew 2l water container, it's a little bit more and made in Japan but worth it. The Platy is still a damn good piece of equipment and still highly recommend.
It screws on but doesn't fully seal unless it screwed on very tight (uncomfortably tight) I use these container types in combination with the Sawyer for gravity fill of other bottles/containers so any leaking will cause me some contamination issues My understanding the earlier platy worked great with the Sawyers but platy changed the threads to a non-standard threading a couple of years ago so I've been told as to the problems I have experienced. Platy still a recommended water container plus it's American made