I'm partial to the Calmini bumper. It's heavier steel than the ARB. 1/4" plate between the uprights and 3/16" for the outer wings. If you get it plan on aftermarket torsion bars to carry the added load. I wouldn't worry about a new bumper unless you are planning to mount a winch. The stock bumper has better approach angles, is lighter and more aerodynamic for fuel economy.
FYI. Bumpers replace the entire stock bumper. Grill guards bolt on in front of the stock bumper and do little more than protect you from shopping carts.