I really liked it, though it is very sweet, so you would not be able to drink too much of it at once (or I couldn't anyway).
It was pretty cheap, a few Australian dollars (with a 20cent surcharge on cold drinks), and I figured that it would be fun to give it a go. I love melon flavoured things. You may have seen the melon cream mochi post previously.
In Japan by the way, according to this bottle, it would get recycled with other aluminium products. That's right, this is made of aluminium, not plastic. I quite like the feel of an aluminium bottle, and the lip of the bottle cools each time you take a sip, which would be really nice in Summer (it has just become Winter here in Australia). Maybe that is why it says 'Getting Cool!' above the name : )
If you are curious about the English on a Japanese drink, Japanese people seem to enjoy English in their advertising. It is exciting and exotic!
I would give Melon Soda a 4/5!!!