Imperial.
And heres my reasoning:
With Rebels i feel like most of their tools are lackluster or flatout bad for the cost, the Xwing itself being the exception.
With Scum they almost completely lack ship synergy, so its a group of single-pilots that happen to not be shooting each other. While thematic, its kinda odd. The few mechanics they have that share effects are never seen (least i never see them).
As an Imperial player i feel like the only truely bad apple i have is the TIE Adv V1, NONE of them appeal to me in the slightest but i can use everything else to some degree and make it feel strong. I have like 20 lists i literally just roll a D20 for on casual play and without even trying i made about 10 of them feel like i was trying to be super competitive, when i was actually being more janky.
I dont know who has the absolute best list that is super difficult to beat, but i feel Imperials are the best faction because they have so many choices right now. Which feels SO WEIRD to say....
Edited by Vineheart01