Joining the conversation late:
We faced the same question earlier this year... continue with plastic bottle fizzy water or get a sodastream. We're glad we changed, the recycling bin is much less full of single use plastic and the fizz gets used everyday. West Yorkshire water is lovely.
I remember adding sugary flavours as a kid, and that the "cola" or "lemonade" never tasted as good as the "real thing" (whatever that was). It was the experience of nasty flavourings that left me feeling sodastream was a bad idea... but realising that all I wanted was carbonated water helped me take the leap.
It's the reduction in single use plastic waste that drove me to do this, that the water tastes great is helpful.
Where we live we have several cooperative community shops that do refills of lots of household products, which combined with having a grocery and butcher in walking distance has helped us to reduce waste massively.
Our experience of buying a sodastream for fizzy water has been good.