It definitely tastes different from the bottle than from the fountain.

I think out of the fountain it's gonna be a little watered down for a couple of reasons:

• I can only imagine franchise owners set the fountains to run a little light on syrup to save money
• the ice is gonna start melting as soon as the soda hits it since it's not chilled below freezing, and the dissolved syrup will lower the freezing point of water like salt does

The bottle has also likely been sitting around for a few days to weeks, and more of the carbon dioxide will have converted to carbonic acid, which will affect the taste.

The recipe may actually be a little different for the fountain syrup vs the bottled stuff for these reasons.

If you've never gotten a fountain drink without ice, it's worth trying. It goes warm quicker but won't get watered down. I used to think people who asked for no ice in their drinks were just picky. However, I recently started ordering my drinks that way because I'd sometimes notice a chemical taste as the ice melted and it'd sour my stomach pretty badly. That never happens when I get my drinks without ice.

I don't think any of this is unique to Baja Blast though. Pretty much every soda tastes completely different between bottle and fountain, and also with or without ice.