I love my Nalgene bottle for the gym and work, but a Smart Water bottle is so much lighter for the trail. It’s threads also fits my water filter.
I’m always looking for the next big “huzzah”, when it comes to lighter or easier gear.
Smart Water bottles for me, too! Especially the ones with the rubbery sport nozzle, because they are ideal for backflushing a Sawyer mini filter without having to carry that heavy syringe.
I am just light on everything else so I can muscle all the water I drink. I'm ashamed to say I often start with 5 liters, even when there is a refill point.
@Bonfire Sawyer Squeeze water filters can be back flushed. They come with a plastic syringe for this purpose.
You can use a Smart water bottle or similar with the flip top "rubbery" kind of "Sport Cap" instead. It's almost as effective. The pull top sports caps don't really work for this.
Sawyer also sell (sometimes include) a coupler that you can use to backflush with a Smart water bottle or similar by screwing them together.
Most disposable water bottles in the US use the same thread for the cap and Sawyer filters also use that thread.
If you go sawyer I highly recommend considering the CNOC Vectro as the dirty water/squeeze bag instead of the stock mylar bags which have a number of problems.
I also recommend adding a filter washer such as the Camco 20183 1" Hose Filter Washer between the squeeze bag and the filter to keep the larger particles out of the filter...and in any case carry a spare washer because they are easy to lose and the filter doesn't work well without one.