It's never a simple as x is good y is bad is it? The RCF 15"s are excellent, there's no slowness in the 735 or 745 but they are £1000 each, plus you don't a sub so no matter how good or cheap the alto sub is it's an extra cost and storage/haulage.
¿puedes hablar español Tubster, donde en el Sur tú tocas con tu groupo?