I decided to purchase this armband because I go running in the gym quite often, and I wanted somewhere to store my iPhone 3G, so it wasnt rattling around in my pocket all the time.
Overall this product is exactly what you would expect. It fits around the arm well and the velcro is strong enough to withstand sustained running without falling off. It houses my iPhone 3G well and it doesnt rattle around whilst its in the armband, and I am still able to use the touch screen through the protective layer on the band, which is nice.
My only complaint is that its hard to access the volume buttons on the side of the iPhone and the on/off button on the top are hard to access as there are no cut out access points in the armband, so you have to guess where they are and hope for the best. The armband also contains a slot for a key. It really is just big enough for one key, but as long as that isnt a problem, then theres nothing else that I would say against the product.