Whats the best roman faction in RTW?

[Garvanko]

Brutii is the best balanced. Their position in the map means they will benefit from the vast wealth of the Med, while their temples generally provide the benefits that are required in a campaign.

Scipii obviously for weapons upgrades and sea trade. Close second

Julii has the best temple for traing Generals and Governors - Jupiter. But their growth and happiness temples are only good either early in the game or late.