A good deal if you grab some hammer gel flasks, and can handle refilling your own flasks. There are rumors that if you are on the trails in forest park, you might see a wild eyed man with very short hair downing a whole bottle of the espresso flavor.
I prefer to fuel on whole foods when riding, homemade rice bars etc. When I ride, this gel is in a 5 shot flask in my jersey pocket. Gel packets are sticky trash in my jersey or accidently dropped on the road. I mix flavors fo Hammer Gel in a flask or on their own. Easy to use, dose how you need it. Great for that emergency to avoid the bonk. Not a big fan as using this as only fuel, more of needing a quick blast to get over the next climb or long stretch of fast tempo. I always have a flask in my swim bag or in my jersey, period. I've been a Hammer Gel fan for over 15 years.
Use on most rides 3-4hrs or longer, up to 600km brevets. Also on short & fast group training rides. easy to get down with out the mess of several empty, sticky single use packages getting all over my jersey pockets.
cons, hmmm, need more flavors?!!!
I had been using single servivg gels but for riding in the winter it was a real pain to try and pull one out of my jacket with winter gloves on. It's a lot easier to grab a flask without issue. Added bonus is that it does not create any litter. The product itself is palatable and agrees with my stomach. I actually like the taste - Espresso - and the caffene helps to keep me sharp. I mix in a bit of water to thin it out a little so it dosen't get to thick in the cold.