1. Economic Position - They're all equal. Brutii are good due to location near Greece and Macedon but Greece and Macedon can be hard to break. Scipii have an advantage in quick ability to conquer Carthage and Sicily but there their advantage ends. Numidia is easy to conquer, but poor. Not until they reach Egypt or Spain do they get much money again. But a good player would secure Greece with Scipii, and then they're probably the best from an economical perspective due to both being able to conquer Carthage and Greece areas. Julii however aren't that bad either as they can conquer both Gaul and Germania at the same time, and do it fast due to the barbarians not having wooden walls and being generally easy to beat in the game. A skilled Julii player would also secure Carthage (and perhaps also parts of Sicily) before the Scipii does, and should therefore be able to get a flourishing economy easily.

2. Strategic Military Position - The Julii can conquer MUCH from their position, although every settlement they conquer might be poorer. If they take Carthage too they should have a really good position. Also for most conquests they don't need naval superiority to win their wars - therefore their position is among the better. Scipii have a problematic position at the start due to needing naval superiority in order to transport their troops between their starting settlements. An average player would conquer Carthage and then Numidia first. When going for Numidia the strategical position is bad due to Scipii having to spread out their forces much when conquering such a large landmass as North Africa, and they might end up sharing borders with Egypt if they go to far - or if the Egyptians go too far. A better Scipii player would conquer much of Greece and Macedon too early, and then secure what's probably one of the best positions of the romans. The Brutii are in the worst starting position but can build much out of it. It's hard for them to conquer Carthage and north africa early, due to long transport distances. Their only really viable alternative that doesn't stretch their forces too thin would be the Greeks and Macs, but once they're down the Brutii have so many options that their formerly problematic position is in many ways compensated. However the northern Balkans area is a problematic area with few borders unless you stay at the Danube line or go all the way north into Germania and conquer Scythia up to the Volga, so there you have some problems again. The other alternative is to establish a foothold in Asia minor and go east - an alternativ which can also be problematic until you've taken at least 2 settlements in Asia minor. As I see it, all are quite even here as the provinces Brutii can take easily are so good that they've got an advantage over the other romans even if they're holding fewer provinces after the first game years.

3. Temple Bonuses - Scipii have an obvious advantage in the Decere and Corvus Quinquireme. However I've personally not needed any better ships than the Quinquireme as most AI enemies seem to neglect their navies. Also most temples built have to be happiness only temples on harder difficulties, and there all 3 roman factions are equal.

4. Gladiator Type - usually a legionary is better than a gladiator to fill a spot in any roman army, so gladiator type really doesn't matter. The julii and scipii gladiators are probably the best, but hard to access. The brutii gladiators are lighter and fill a more unique function in a roman army due to it's light equipment and strong charge unlike most roman line troops who have low charge and strong defence. I'd say perhaps Brutii are best here but I rarely ever use the gladiators, they're really not important enough to determine which roman faction is strongest.

In conclusion I'd say all 3 roman factions are about equal in strength and difficulty.