It is worth stressing that anyone with an iPhone should have a case of some sort, the day this case arrived in the mail here, that very morning I dropped my iPhone 4 for the first time, and all I could do was watch in horror as it fell to the floor, my muscles frozen, unable even to move my foot to brace the phone's fall. Think of all the times your phone is out, you tapping the screen, holding it up for friends, taking pictures. Sooner or later, it's going to drop.
That said, I'm extremely happy to have my new iPhone 4 wrapped in the Otterbox Defender case, and as usual they've done an outstanding job with this version.
The shape of the new iPhone 4 has let them come up with what I think is a much more user friendly case. The feel of this case is much nicer than that Defender cases for prior generations of iPhone, which were themselves darned good. The silicone exterior is textured, providing for an excellent grip, without being too tacky to the touch. It slides in and out of my pocket far better than prior models, which I generally would never use without the included holster. Having used my iPhone 4 without a case for a few weeks, I had become accustomed to sliding it into my pocket, and discovered that this new case supported that habit quite well. The downside though is that the case isn't quite as grippy on flat surfaces, quite often I would have my phone charging in my car, and have the case resting on the armrest between the front seats. Prior cases would stay put around corners and hard braking, this new case has a harder time staying put, but overall this is, to me, an acceptable trade off.
The included holster has also been redesigned, the original iPhone version had the phone sliding straight down into the holster, the 3G version had the bottom of the phone sliding in at a slight angle, then the rest of the phone clicking into place. The iPhone 4 version requires that one edge of the phone slide into place, then the other edge snaps in. This has the advantage of the phone screen either facing the inner part of the holster, totally protected, or unprotected and exposed, but viewable to the wearer. I actually prefer the screen facing outwards, as it makes it easy to see who is calling, quickly check the time, read a text message, etc. The holster now also doubles as a stand, which has come in very handy for my wife and I to watch baseball games via the MLB At Bat app while dining out.
The case's built in screen protector has also been redesigned, incorporating a textured surface on the inside that eliminates any bubbling, but does not interfere in any way with the touch screen operation.
The Defender case, like prior models, is a multipart design. It includes an inner polycarbonate shell, which includes the protective screen cover, and a silicone skin which goes over the hard shell. The ports on the phone are well protected from dust and accidental exposure, small flaps easily peel back to expose the dock connector, headphone jack, and mute switch. The volume buttons on the phone are also easily accessible through the case.
As usual, Otterbox also has the Commuter and Impact series cases available for the iPhone 4, which offer less extreme protection for those who already pamper their phones, these models do not include a holster, but are still fairly rugged. All models are currently only available in black. Full details on these and other offerings can be found at Otterbox.com.
In summary, I think that every minor complaint I may have had regarding prior models have been addressed with this case; it works great with and without the holster, the mute switch is accessible, the phone can fit into the holster with the screen facing outwards, and the fit of the phone within the holster is excellent.