This is a good value soft case, the case is silicon and many of the reviews attached to this product talk about leather and linings which this item does not have? Anyway, for the price it's soft, easy to fit, great value and will protect the back and sides of your iPhone4. You'll still need a screen protector which is fine. I liked the packaging, easy to get into without the need for a trip to A&E :-)
It comes in a range of colours, all attractive, is easy to slide onto the phone. If I had to be critical, I'd have liked it to fit over the bumper that came with the phone, or at least fit snugly without the bumper in place, I found the sides a little loose, not enough to come off but enough not to be attractive. Hence the four stars instead of five.
If you want a great value case, like a range of colours and the feel of silicon, then go for it. There are more robust items out there, but not at this price point. It works well and I will use it, but for travelling I'd want something more sturdy. As an everyday case for around the house, school run and travel to/from work, this is fine.