I think agression is more due to environment not species.
But I don't know for sure.
I know that my fronts were very skidish and shy. Almost insulting how they hid from me every time I tried to watch them. Any movement in the room and they would dart for rocks to hide behind.
My girlfriend thought they were so boring, said "those fish are so lame, they don't do anything".
She loved my SA/CA cichlid tank though.
I would like to try Mpimbwe sometime.
There supossed to be very freindly and out going.
Not as vivid blue but atleast they might like me.
Burundi are the least expensive and the lowest in demand, due partly that they have been around the longest.
But the males get the biggest monster Hump on their foreheads. I think there pretty cool, if you could ever find true F1's and not just generic ones from the lfs.