I've tried:
Wellbars
Training treats (Oat flour, garlic, honey, sesame oil, olive oil)
The Wellbars are really dry and mostly tasteless. The training treats on the other hand are really good.
A friend of mine tried the training treats and a sweet potato chew. He said he could see himself sitting back and having some of the training treats with a beer, but the sweet potato chew was too dry. Haha.