which do you think is the best faction?

[Craterus]

And about Egypt, I always attack them through the desert. Best way to cripple them seems to strike at Egypt itself, either marching for years through Libya and Tripolitania or making an amphibious assualt

The Romans (Scipii) have done exactly that and tried to take Siwa on numerous occasions!

[RollingWave]

In terms of vanilla game setting disregarding everything else best is probably either Brutties or Egypt while worse is a hard call depend on what ur judging from, but it's probably either Dacia or the Greeks (the Greeks cause they are in a extermely shitty situation while Dacia because they usualyl can't go anyhere though often ppl don't bother to kill them either)

[Craterus]

i wouldn't say Dacia are the worst faction...
maybe the Greeks (campaign wise) but they have a good selection of troops