Yeah, works well for the iPhone 5. One thing to keep in mind is that it is smaller and somewhat more expensive than many other external batteries. It's very portable and matches the black iPhone perfectly, and has a nice build quality as well, but you will likely only get one charge out of it before you have to recharge it. If you're looking for something with a bit more power (and a lot more bulk!) I'd recommend the Monoprice 9000mAh USB External Battery Pack, which has more than twice the power at a lower price. If you're looking for something that can give you a full charge and is very mobile and nice looking, though, this Mophie is the one you want.
I don't have an iPhone but the power brick works well with my Samsung. It has a normal USB port you can plug the lightning adaptor into. The mophie will keep my phone going between two and three hours of heavy internet use with a poor signal or will charge the phone in standby mode in about an hour or 90 minutes. Its not heavy or cumbersome to carry but I keep it in my backpack not on my person. Hope this helps.
The morphie power station has a USB connection to supply power. As long as your IPhone 5 has the ability to connect to a USB it will work great! (The reason i say this is that i understand the new Iphone 5 has a different connector) I have an IPhone 4S and IPad 3 that I use the power station on. You will enjoy it.
I don't know the battery capacity of the new iPhone 5, but 4000 mAh should refill it, probably more than once. Please use only New Apple supplied cords. Your old charging cords won't work. Apple added a proprietary chip that Must be present for any cable, 12 volt car charger or AC wall charger to work in the new iPhone 5.
What you want to look at are the mA's output of each of a battery's outputs. Older phones needed 500 mA, the 4S iPhone needed 1A, other phones need 1.1A while most tablets need 2.1 Amps or more.
Also, expect to lose about 30% of any recharger battery's listed power. This is due to both the heat created by the power transfer and the "cost" of the inverter which is converting the listed power into the usable Amperage which is being delivered from these batteries.
Please ask more questions, should you need more answers. Good Luck! Gabrielle