Which is best for long-term storage of soda: cans or plastic bottles?

I looked into alternatives such as a single-serve soda fountain. Even a single-serve residential unit seems too expensive and bulky. I tried Soda Stream, but their syrups are not as good as the name brand sodas. I'm still open to alternatives.

Do I go with can, plastic bottles, or do you know of a good alternative?

Jeanette Isabelle
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I'm not sure whose twisted idea it was to put hundreds of adolescents in underfunded schools run by people whose dreams were crushed years ago, but I admire the sadism. -- Wednesday Adams, Wednesday