Factions are brilliantly designed, the campaign mechanics are very nice too. My only issue is that one or two units (like athars chosen) are stupidly OP at the moment and either need to get a nerf or have their price raised in multiplayer.
Overall it actually looks like a lot of work went into this DLC and I was more than happy to part with my cash for this faction pack. This is what people wanted, CA, lots and of new units to make new factions unique rather than having 4 new units with the rest of the roster being copy pasted from other factions.
Gets a big thumbs up from me.