ʙʟᴀᴢᴇ

I think the Goku's and Gohan's fusion will have slightly advantage because of Gohan's Beast Instinct and the Fusion Dance fused fighter will get Unfused if their fusion partner lack ki that need to keep the Fusion Working. And in the case of Potara Earrings Fused fighter will have a time limit of 30 min and also if the fused fighter used too much power that potara Earring can't handle then it will lower the fusion time.

So in Gohan & Goku's fusion will have access of Almost Unlimited Ki so the fusion will last longer.

And in the case of Vegito's it will have access to use limited Power that potara Earring can handle with a time limit of 30 min but it has extra boost in power of the opponent if they are rival.