Depends on the individual fish and at which size they're at. But if a male Con was able to grow to the size of a full grown male Jag, I think we'd have a clear winner (maybe) lOl
Depends... I've seen some really tough specimens from all four, but it is hard to say pound for pound. At 4" a Convict is more mature than a 4" Jag. I'll go with a Jag if all at full size, but that is not what you asked. Since Convicts only get to about 5-6", we will need to compare them at that size. They are all pretty equal at 5-6" IMO, but I'll go with a RD.
I've owned all except Jags, & My RD's have all been nasty!
I've had a few cons that were pretty bad ass, but not psycho like my RD's.
My Cons only get crazy if they're going to spawn.
Had a pretty big GT(my largest fish to date) he was really pushy but not a killer.
My friend had a tanks full of Jags, but they weren't glass bangers.
They were actually sort of on the shy side.
Pound for pound, I'd say the Con, they don't back down from anyone, except my RD's.
Take these suggestions with a "grain of salt".
Every fish has different temperaments/personalities.