2 different types of champs so hard to say. Both need high sig. one is suicide friendly and one is not. Void does things omega could never do and vise versa. Void is incinerate immune which seems to be popping up more and more. I think it really comes down to your roster and what you need. Both are great options and worthy imo.
Comments
Omega will get you much further in the game than Void. Double immune. Heals with suicides and the right masteries.
Also Void isn't as good as he used to be since they started adding indomitable nodes.