I've found a bottle of sparkling water with a dash of cordial added is more refreshing.
I find most fizzy drinks, especially the diet ones are far too sweet, it's like they over compensate.
I'd much rather have a fizzy drink that was less sweet.
If you buy a bottle of sparkling water and add a
small amount of squash, it's much nicer I've found.
Some of the 50% fruit ones are nice, peach and white grape.
Its cheaper too.
Sparkling water is only about 17p a big bottle.
You have to drink it fairly quickly as it goes flat, if left.