The TOW is a much larger missile, with longer range and a more powerful warhead. It needs a Humvee or a Bradley to have enough mobility to be useful.
I thought the tow's range was only like 3000 yards and actually that's hard because of the need to optically guide it -- you gotta keep your eyes on your target throughout the flight of the missile. You can't have trees or hills in between because of the gunner's need for line of sight.
Since the gunner has to have line of sight, that means he has to be out in the open and the backblast from the missile launch gives such a big signature that the gunner is a sitting duck.
The javelin (heat signature?) locks on and then ELEVATES and comes down on the target. In the meantime, the gunner who fired it is running away to fire again and/or hide. I believe the Javelin's effective range is further than the tow's supposedly was.
We need an infantry guy in here. Hey travis, can you help us out?