It's basically the same as the iPhone 4, except bigger to fit the iPhone 5, and different cutouts to use the headphone jack which is now on the bottom, and to adjust to the smaller charge port. I loved my iPhone 4 otterbox case and it lasted me several years with only normal wear. As far as the bulkiness goes, if you do purchase one, just get used to it. And know that it's keeping your awesome phone protected.
I don't have a photo of my iPhone 5 in otterbox case yet. I'll be receiving the case possibly tomorrow.
But the iPhone 4 otterbox case you can look at photos. It's basically the same, but the iPhone 5 case will come with a back piece to connect it to the case and attach the phone to your pants - which is an awesome feature.