I’m not sure if it’s isotonic, but I’ve used it a few times now.
Taste wise: it has a salty bordering on slightly sour lemon flavor. If it’s cold and blended with a bit of ice for a hot ride, it taste like a margarita (in a good way). As it gets to room temperature, it starts to taste a bit like a lemon warhead candy (similar to the Beta Fuel). It’s pretty easy on the stomach though and I didn’t have any adverse effects.
Energy wise: it’s very smooth and has a different digestion profile compared to Maurten. Much slower and smoother in my opinion, but it has tended to make me feel “buzzy” for many hours afterwards even in situations where I’m burning 900+kj per hour where I should be working through it all.
After having tried all the superfuel drinks, I’m still back to regular Skratch or even just electrolyte drink. I’d rather just eat the regular food and I feel better and get less palate fatigue when I go this route.