The Newer Technology Power2U AC/USB outlet will work on any 15amp (20 amp optional) circuit with a 16 cubic inch electrical box. This is important to note this — because it's fairly deep and it will just fit in many standard boxes. It's typically a DIY install for most, and believe me I tried. However, I had to bring an electrician in to install mine — our house wires were spliced in such a way it didn't seem as clear cut to me, so I bailed on it. The good news is that OWC, the distributor for them has easy to understand and follow videos - and it's really an easy install if you follow along.
Mine was a special case, so I'm glad I had the pros come in. My advice is to watch the videos, see if it feels like something you are comfortable with. If not, let the pro do it — I had my guy install ours for $50 — it took him about 30 minutes, and even he was impressed with them.
Now, the good news is that this thing works GREAT. You can literally have two USB 3.0/2.0 devices (usually iPads overnight in our house) along with two standard AC outlets all plugged in at once. It's a fantastic solution to those who need more outlet space and abilities to charge their USB devices. They support the standard four-pin type-A jack USB cables - just like the ones you plug into your computer, iPad/iPod power bricks, etc.
We installed one in the kitchen where we usually like to grab some quick power, and also one in the family room for when we are relaxing and need some extra juice to get through till the end of the day.
I didn't do any timed tests to see if there was a difference in charging speed, but I didn't notice anything significant when charging the iPhones — they charge VERY quickly. The iPads typically charge in an overnight situation, and even with their dedicated adapters, they tend to take much longer to charge. I'd say if there is any difference in the speed of charging, it's probably negligible. I also tested it with my Flip Mino USB camera, and it seemed to power and charge it just fine as well.
If you have small children, the outlets will work with the child proofing plastic nubs you put into the 3 prong outlets. The USB shutters are spring loaded and close when not in use. Also, the shutter turns off then USB ports when you remove the cable. These sliders are a little bit difficult to slide open - so even a kid with great dexterity will have a bit of difficulty with it. If it was a bit easier to open, it would be nice for my hands. It's a trade off - but safety first in my opinion.
Update: The newest version of these have the NEC safety shutters on the AC receptacles - so no plastic child proofing required. The particular 15A version we tested are now on clearance - so if you don't need the NEC safety shutters, you can get the model I tested at a deep discount.
I've really enjoyed having these installed in two rooms of our home. They make charging much easier in a multi-device, multi-person household. We have 3 or 4 devices charging at any given time, so the ability to plug in directly is a boon.
These are reasonably priced, and if you are looking to make an upgrade to your house that you will use daily — this is an excellent one to make. Personally, If I was building a new house - these would be in every outlet - because you always need a place to plug in USB.