SSJ4 Vegito

I'm going to say Future Trunks. Trunks & Goten would give him quite alot of trouble though. I also think that Gohan was holding back with Goten because, as you can tell during their fight Gohan doesn't have an aura even when he transforms. Although later I think he does but it's only one panel in a seperate fight but I'd still say Gohan was restraining himself because of where I placed Vegeta & Trunks' Base forms (Cell Games) which I just think is far superior to Android 18 even if handi-capped. I'd say Trunks has the big Power advantage but Trunks & Goten work good together, so I'd say Trunks (Future) by a small margin. Since he really takes battles a little more seriously and is a better fighter.