Darth sion in sith raid

It's been a while since I've managed to go up against sion in the sith raid. I typically start the raid with my resistance team against nihilus and avoid reentering the raid until the final stage when traya is the only surviving boss as my other teams can barely do much damage elsewhere. How difficult is sion in comparison to nihilus? The reason I ask is that I want to get as much damage in as possible after nihilus and before the final stage but like I said before I have only a few toons strong enough to handle this raid and dont want to risk doing menial damage when I could be doing more in slightly easier areas.