i've had no problems with soda taste, and I've been using root beer bottles, arguably the worst to get rid of. a soak or two with oxiclean and that does the trick for me.
I've had a couple bottled in plastic since january and they seem to be sealed just fine
bottle - some odds and ends
Primary - Belgian Pale
Secondary - smoked ale, christmas ale
on deck - brrrrr-ley wine