I myself prefer SA/CA
over old world. It's mainly due to the fact they grow large and have attitudes to match. They are super smart and are so interactive. Also they for the most part are very hardy fish and very easy to raise to maturity.
The down side is you can't have as many as you could with the old worlds. In a 50 gal
. You could keep any of the larger species for about a year before having to rehome. Or you could have a few of the smaller/med size mild temper ones.
you can't go wrong with new worlds even if it's less fish the interaction more then makes up for it.
Anyways hope more people chime in for ya. Good luck.