Like most people I've tried a few cases for the iphone 4/4s, without much luck. This will definitely protect your iphone from a drop of significant height as the leather is padded on the inside. The velvet also won't strach your phone and the belt clip is sturdy. Additionally it won't slip out if you happen to tilt it upside down - its a very snug fit.
One thing I will say is when I take my iphone out it makes me feel naked, as if somehow I've just exposed myself, so i bought this case:
at £3.90 this is 10 times better than the SPG neo hybrid case I bought costing me £20. It does fit inside the pouch, but you have to push it in and your gonna have a hell of a time getting it out - I managed to figure out a trick that does it but it looks like it'll be a while before the leather stretches out enough to allow me to keep it on while "holstered". (put it in upside down so the charging port is exposed and the headphone jack will fit in through the two speaker holes in the bottom, then grab both sides of the phone tightly, where its exposed at the top and push down on the top part of the pouch(not the sides) - one things for sure, it aint gonna move with this case on).
Alternative thinner case which WILL fit inside the pouch is called the "pinlo slice 3£