Glass bottles are the best but are rare now I think 😀
I don't drink soft drinks that much but when I do its from a glass usually ...depends on where I am at 🙂
I have no real preference for glass/plastic/can (based on taste anyway). I'll drink pop from any of them without issue. (I sort of prefer plastic though for the simple fact that the plastic bottles tend to hold more than cans. Cans have 355ml or those almost worthless ones of like 128ml. Bottles are 591ml, 710ml, 1 Litre or 2 Litre. And at times you can get 6x710ml or 2L bottles on sale. 2$ for 6x710mls or 99 cents for a 2 litre.)
But I don't care much for fountain pop. I find it goes flat pretty quick, doesn't always taste great and they tend to put ice in it (which dilutes the taste and makes it go flat faster) unless you specifically ask for no ice.