I think it's a matter of just being true to what each character is about.
Juggernaut: once he starts moving in a given direction, nothing, Nothing should be able to stop him. This is what Juggernaut does (at least as I understand it).
Hulk: what Flash is to speed, Hulk is to strength. The madder he gets, the stronger he gets. He is strength incarnate; this is what Hulk is.
Ergo: in any other contest of strength, Hulk should win. But when it comes to simple, straighforward pushing, this, by my definition, falls into Juggs' field.
Thus, Juggernaut for the win. Hulk may get stronger, but Juggernaut's forward momentum is, imho, an absolute. In a sense, Juggernaut also always gets stronger, stronger than Hulk, but only in this limited fashion.