For my use, nothing is better than standard soda bottle, but I use a Steripen Classic.
I don't know why the new Steripens don't use this design? The neck gasket makes it so much easier then the dip and stir method that the newer models require.
Soda bottle are cheap, light and the screw cap is much more reliable than the Gatorade style caps which break when dropped or start leaking after a month of use.
I beat the hell out of mine and have never had one fail. Can't say the same for other bottles I've tried.