I have two Otterbox cases for my (now sold) 3GS - a commuter and a commuter TL. They were utterly fantastic, and the port covers are an ingenious idea. HOWEVER. The renders for the iP4 cases look hideous, and don't offer sweet colours.
As with the iPad, expect a looooong wait, and even longer if you're wanting different colours. It's a shame really, as I already budgeted for an Otterbox and hoped for one to be released for launch week.
As it stands, unless the commuter case gets a makeover with colours, it's a bumper for me. Also, the metal buttons on the bumper are a cool idea.
I'm also waiting for the iPad commuter to comes out... I can feel my beard growing....!