Which is going to require more runway (thinking that you only have to be say 30ft in the air to miss the aircraft).
In most cases the aircraft will take off and climb at a speed much below the nominated rotate speed, and so, in most cases, I think your best chance is to continue and climb over the traffic.
You may have reduced manoeuvre margins, and be up the creek if you then have an engine failure, but if you're at V1, how many times would you be able to stop in a shorter distance than you could be airborne (given that this is an emergency situation).
It all depends on where the other aircraft is, your performance, all those sorts of things!