I've used Hammer, Gu and Clif Shots and prefer Hammer. I like their flavors better and the texture reminds me of pudding. My husband has used all of those and likes the single serving GU, but finds that if you are using a gel flask it doesn't flow as well as the Hammer. Clif shots worked well too and I really like their "anti-litter" packaging, but both my husband and I get a little gassy after using them.