Fits my iPhone 4s really well and offers a reasonable level of protection whilst adding very little bulk. Also gives you a better grip so you are far less likely to drop it. The material is not that rubbery and slips in and out of your pocket easily without picking up lint!
Connected immediately to my iPhone and has good volume with no distortion and sounds really good considering size and cost. Outside I have found it will work up to 20 metres away with line of sight and indoors several rooms away.