i cant really say what is good... but I think that type 2 plastics (cant say for sure, please check) are better than 7 to drink from. However here is something you might want to do some research into. There are types of organic plastics out there, but they probably become inorganic because of the way they are processed.
I feel its safer because I know the medical industry will often use organic sourced plastic in surgical proceedures, rather than oil sourced plastic. This is because people dont have the allergic reactions with organic sourced, that will happen with oil sourced plastic.