I started my server really late so I don't have Madara Edo yet.

Personally though I am using Orochimaru GNW in my pos 2/3 spots depending on my team I am using. And realistically if you do not have Madara at 4* then Orochi is the best choice in my eyes because I think 3* orochi is way better than Madara at 3*. It isn't stated in the actual game but most of the abilities that the Kage get from Orochimaru summons are based on the Breakthrough versions, lesser versions but still BT versions. If you can get Madara at 4* I think he does overall more damage. The weak spot on orochi is himself, you kill him all his Kages go * and if you cant survive to round 3(if he died on round 1) then it's Curtains if you cant manage to kill any of their team after that point.

Unfortunately I don't have any experience with Obito GNW.

I use Jiraiya a fair bit also, I think he has his own uses and it depends on what you want to really do with your team. I bounce around both of them but at the end of the day I prefer using Orochi GNW just because of the sheer potential he has if you keep him alive.

Have a good day!