I've been using EndurElite products for about 2 years and the Sustain X is one of my favorites. It is hands down the best endurance product I've ever used. I'm able to do my long runs without any significant drop off in effort as long as I'm fueling with Sustain X
SustainElite works well when I am doing a 45 minute workout or when I am running at least 4 miles or more during any one session. When combined with ElectroElite, you're pretty much unstoppable out there, assuming that you are keeping up with your nutrition :)
This is now my go to race and big training day fuel. Mixes easy, lots of carbs packed in a small space, taste great and no stomach issues.