Oooops -- bad math. 6 soldiers in the rear, and squeeze one more in behind the driver = 7, not 9. Plus three crew. 10 total in the Bradley.
ok, the Hummer is a small diesel powered truck. That means wheels. It is narrower, faster, and smaller than the 113. Its armor can stop rifle rounds, but not RPGs. The Hummer can go through narrow streets where the Bradley and M113 can not go.
The M113 is tracked, diesel powered, and amphibious if everything works right. Its armor will also deflect bullets, but will not stop the RPG. It will narrow the RPG round to a thin stream, saving most people inside it, but not saving the unlucky guys that sit between the entrance point and the exit point.
The Bradley is large, turreted, and heavily armed. It's armor is pretty much proof against the RPG. It is tracked, and very loud. Now don't get me wrong, all diesel engines are pretty loud, but different vehicles have different size mufflers, and different size engines. The current versions of the Bradley are mostly not amphibious.
They have different characteristics, and different uses. If you use a Hummer in a stand up fight: it is a big mistake. If you use a Bradley in an attempt to chase down your foe in a city, shame on you, it is a big mistake. In a lot of ways the M113 sits between two stools. If you want to dash quickly and quietly to gain information, you can't. If you want to engage in a stand up, the bradley that provides overhead cover and all round armor is much better. If you want to get close enough to see, but use something else to do the killing, the M-113 is a good option, but you will have to open up the hatches, and take enemy fire to shoot back.