Tailwind is my hydration/nutrition go-to for any kind of ride and I seriously don't leave the house without it! I use it as my main and preferred source of calories while on the bike year-round. It's just easier and faster for me to meet my caloric intake needs with liquids this way than having to think about taking a gel or solid foods every 45 minutes, etc. I will still bring Rx bars or Maurten gels as secondary sources of food or rely on gas stations as a mayday option. Of course, everyone has different needs/preferences for nutrition when exercising but I've relied on this exact strategy for the last training season or so and I've been using Tailwind for over three years - it just works for me.
One scoop is 100 calories (and 35mg of caffeine for the caffeinated flavors). The recommendation is 2-3 scoops with 24oz/710mL of water per hour for longer efforts and 1-2 scoops for per hour for shorter efforts. I use two scoops in one standard size bottle for rides up to 90 minutes depending on intensity and weather. Anything over 90 minutes (for me) will require two or more bottles prepared in the same way. The information on the back of the bag is really helpful for mapping out your calories - it can't get any simpler. You can't go wrong as the ingredients are simple and clean with absolutely nothing to hide - the bad doesn't lie. As far as I can remember, I've never had any stomach or GI issues when using Tailwind. Luckily for me, I don't have any dietary limitations either, so really anything is far game and I tend to stick with what has worked well.
I'd recommend Tailwind to anyone. Colorado Cola is my favorite flavor by far - really similar to Coca-Cola soda! So, if you are unsure about a 30 or 50 serving bag or maybe you haven't tried Tailwind before, there are also single serving pouches available. Try it! It's definitely better than Gatorade or just plain water.