Soda water is like mineral water without all the mineral aftertaste and is good for those with delicate taste buds. Also, as it's generally on tap as a mixer in pubs you can ask for a glass of it and you get given it for free! So it's good for those with delicate wallets also.
soda water is carbonated water with a small amount of baking soda added. i don't know why they add the baking soda, but oh well. i'm sure someone will be a smart ass and go link me to wikipedia and then i'll find out.
In the past, soda water was produced in the home by "charging" a refillable seltzer bottle by filling it with water and then adding carbon dioxide. Club soda may be identical to plain carbonated water or it may contain a small amount of table salt, sodium citrate, sodium bicarbonate, potassium bicarbonate, potassium sulfate, or disodium phosphate, depending on the bottler. These additives are included to emulate the slightly salty taste of homemade soda water. In the UK Soda Water is nearly always made with Sodium Bicarbonate. Gosh, isn't wikipedia wonderful.
I say soda water because my favourite alcoholic beverage is vodka, lime and soda... Thats real lime juice not that disgusting lime cordial stuff some bars use to masquerade as lime. Although by itself soda water is a bit like drinking air but I've never even heard of the other choice so soda it is.
I once read about an Indian man in the days of the British Empire whose surname (I don't know if he had an Indian surname as well) was Soda-Water-Bottle-Opener-Wallah. This alone sways me strongly towards the soda water. On the other hand, Pocari Sweat. I mean, come on.
Well, did you know that Pocari Sweat was invented by The Great Sweater (literal translation of a Japanese name) of Pocari Mountain? Thought not. (because it isn't true, probably)