I prefer Epigoni because of the extended map and it's historical accuracy, but ROTA does a very good job at creating good gameplay. The character system is okay, not as great as CK2, but that's just because EU:R core mechanics. At this moment you probably played Epigoni, so it would be very difficult for you to just go back to any other mod because of the expanded map and the incredible amount of available factions, but give ROTA a try. That mod does some things better than Epigoni, for example, tirany actually matters, the addition of being able to peacefully annex vassals after some time, the way trading works and the diplomacy tweaks...
All in all I would say that Epigoni is the superior choice, but I would add some of RoTA's features to it.