Barret seems mean and ignorant at first, but he really makes a great friend and ally. He'd also make a great father, taking care of his old best friend's daughter, Marlene. He bullies Cloud alittle, but everyone knows he's just kidding around; even if he won't admit he cares for his allies. Barret had a sad past, and wants to save the world for Marlene, Dyne, and now his new friends who stick up for him.
Barret is a great person to have in your party. He's one of the first to join your party, so you can level him up along side Cloud, and his HP is a great factor in him. If he's at the same level, or even a few level behind, of Cloud, you can for sure say he's got at least 200 for HP above Cloud; but that mostly grows as you advance in level. Getting his ultimate weapon is a bit easier than everyone elses', especially because it's not out of the way. There's more on that in his weapon section, though.