Kensington Black PowerGuard Battery Case with Card Stand for AT&T iPhone 4 (K39260US)

Pros: Nice feel to case. Non slip. Adds heft and weight, but understandable.

Cons: Very poor design on the Micro USB connection. Failed after a few months...now trying to get warranty service. Wish it could still use the Apple connector. Plug just does not go in very far.

Pros: It works and can be great when you need to charge up and not in a car or at home or away from laptop...

Cons: Cheap looking and the card thing is useless. Nothing much to say but it just a simple thick battery attachment.

Other Thoughts: if this was on a special 25 or under...get it! if not, you can find similar items now for less than 35....

Pros: Gives you that extra needed juice to keep your iPhone on for few more hours.

Cons: First thing you might notice is the stand card, what a genius idea! It is not like they were trying to save any space by doing that (the case doubles the thickness of the device anyway). Instead of the card, why not have a little plastic arm.
The opening for the camera and the flash should've been a little wider so it won't cover some of the flash.
It is thick, and adds more length to the phone at the bottom.
Protection wise, good on the back, put the front of the phone is still not well protected. The case feels very plasticy. Some rubber might have helped.
The iPhone's connector at the bottom is covered and replaced by a micro-USB port. On the plus side, you can charge the phone with any standard micro-USB, but you've lost the ability to use all of the iPhone accessories (chargers, docks, etc...).

Other Thoughts: THE WORST PART:
The switch on the back of the case is very cheap and flimsy. It doesn't "click" well. I found it to stay midway most of the time, and it is a bit tricky to turn on or off. This would cause the phone to charge/not charge a lot, and you don't need an expert to tell you how bad that is for the battery. I almost burnt myself when the charger went on while the phone was in my pocket. At that point I was over it.

The product has a great potential, but the very poor execution of the idea keeps it away from being usable. I keep it in my car in case I might need to recharge my phone, but I have a car charger.

Even though I bought it on sale, I feel that I overpaid too much for this piece of junk.

Pros: Love this thing. I have an annual pass to an amusement park, so I take this with me whenever I go there and after about maybe 6 hours of constant use of using the amusement park app while I'm there, my phone starts to dip down quite a bit, but as soon as I click the charge button on this case, it goes right back up to 100% in less than an hour (even while I'm using it). Just to throw some numbers out there, last time, I got there at 2pm and by 7:30pm, my phone was already at about 50% battery. I clicked the charge button and I had 100% battery until 10:30 pm, even while video recording a water show. THUMBS UP on that!!!

Cons: None!

Other Thoughts: You can charge this battery case by using the supplied USB cable that comes with the case and using your phone's USB a/c wall charger, or plugging straight into a computer. You can also sync your phone while using this case. Sweet! Some other battery cases don't let you do that.

Pros: Plastic card feature stands phone in either vertical or horizontal orientation -- all you need is your credit card. (Or the included plastic card.)

Cons: At 1200mAh, it carries less juice than the iPhone 4's own battery (@ 1440mAh). Adds only about 50 points on the iPhone's percentage battery meter before fading away.

Frame and backing are mismatching materials -- the back is an okay matte finish, but the frame is a shiny plastic that tries (and fails) to mimic the look of the iPhone Bumper, and easily gets blemished. It also doesn't match the confidence of the bumper in keeping the screen glass off of surfaces.

Too fat to fit in Kensington car mount bracket.

Other Thoughts: I'm not pleased that I spent $50 on this. Consider buying an external battery instead, which will almost certainly outperform the charging ability of this unit.

Pros: It does extend battery life, but...

Cons: ...not as long as the Mophid did on my old iPhone 3GS

Other Thoughts: I'm just a little disappointed. Form is fine, weight acceptable.

Pros: nice design. alittle bulky, but not half as much compared to my otterbox. credit card stand option a big plus, easily stored in your wallet. syncs very well to itunes via usb micro connector. i paired mine with a screen protector

Cons: micro usb connector only fits into the socket about half way. although it snaps into place firmly it can easily bent or break if not handled with care when removing the usb connector. this makes no sense for such a sleek designed case have such a flaw.

Other Thoughts: i havent tested the battery life yet

Pros: Fits good and has a good feel. Gives a decent charge for when u r on the go

Cons: Looked kind of cheap out the box, only charged 60 percent on a full charge

Other Thoughts: Got for 20, can't complain alot more comfortable than I would have thought. Pretty light