Sym supreme is awesome at r5 and is very effective for certain fights. But for variant 1 you need a better power control champ (yes I know SS has a bit of power control) but someone like majik or doom would be better.
I really didnt use my SS in act 6 at all. There arent very many fights besides the champion boss where he shines. But if you are good with him definatly rank him up he does have alot of utility.