Jobin is cool because you understand entirely why he reached his conclusions. I feel the same way of Pucci, even if you don;t agree with them you empathize with how they they reached their conclusions and went off the deep end. He's charismatic with his daddy-brother face as well as his business mod with Dolomite, Araki really got Jobin to demonstrate both sides. Tsurugi adds another layer to Jobin, his actions and also reaffirming his conclusions about life.
The tagline in pic related also sums up well how quickly Jobin provides a contrast to everyone else in his family and their own goals towards "happiness".
Joshu is entertaining because he's relatable in a sense that we all know someone like him. His heart is in the right place and he genuinely cares for his family, Him being defensive over his family with Gappy, Damo and Kaato are all the little trains of the younger brother really trying his hardest in his own backwards way. He just acts like a retarded spoiled teen who's just growing out of that phrase.