I have an Otterbox Defender for my iPhone 5. Love it. I only use the belt clip when I'm out walking/hiking with the dogs, but it seems to work very well. As far as bulky -- maybe. I'm a small female, though, and it doesn't cause me any problems. To the extent there is bulk, IMO it's a good trade-off for the protection. The only quibble I have with the Defender is that once every two or three months I have to take it apart and clean the inside of the screen protector and my phone screen. Otherwise I start seeing little shimmery spots that look like oil spills in sunlight.