The Speck PixelSkin HD Case for the iPhone 4 & 4S is dubbed HD due to it's high definition grip. Basically it has dozens and dozens of indented squares on the back which in turn is meant to deliver grip.
The first thing I noticed is that the colour variety is brilliant. Different shades of Blue, red and pink are available, as well as just one skew of black, grey and purple. The shape of the case/ skin is simplistic and functional. It feels really nice to hold and doesn't attract dust or dirt, so it always feels clean.
Getting your iPhone into the case is quite a squeeze. So I avoided taking it on and off throughout a week and changing things around like I normally do.
The rear camera, headphone jack, mute switch, speakers and 30 pin dock connector have all been cut out of the case. The camera hole is massive and that is a huge plus because it allows the maximum amount of light into the lens. The 30 pin dock connector cutout is just big enough for the Apple charging cable to fit through, it's hit and miss fitting with docks. This is a slight shame because the case isn't the easiest to remove and reattach. The sleep/ wake button and volume control buttons have been covered by the case for added protection and still function normally.
The grip isn't that prevalent when holding the iPhone within the case. It feels slightly slippery if anything but as I wrote previously it is very comfortable to hold and use. The grip seems to come into play when you rest the iPhone against a surface. Around the bezel the case protrudes slightly above the screen, in the event of yourself resting or dropping your iPhone face down. It's not guaranteed that it will prevent harm but it's nice to see that the screen isn't directly resting on a surface.
Protection is quite substantial. The PixelSkin HD is made from very tough and thick plastic. This in turn adds a bit of shock absorbance but also helps against scrapes and bumps. It's worth taking into consideration that the rear camera is very exposed to the wilderness and so having the case in a pocket against even soft items concerns me. But all in all it does a good job at protecting your iPhone.