Camillan units are far less steady on the battlefield than their Polybian counterparts. When using the Quicunx, Polybian Hastati seem to last far longer without routing and inflict more damage, and Principes are far more effective and disciplined. I rarely field Triarii anyway so I don't bother with that, neither with Equites: what matters is that the bulk of your army gets better during the Polybian reforms. Cavalry can be fought with Samnite Spearmen and other allies\mercenaries\auxiliaries on the flank carrying spears, so they aren't worth bothering about.

The unit you should recruit for every legion you have after the Marian Reforms is the Cohors Evocata + antesignani. It's a fearsome bulk of infantry and far better than what many factions can field.