The internal battery does take a full 10 hours to charge. So plan on setting it to charge overnight or a day before you plan on using it. It uses a fairly common MICRO USB cord for charging. So if you misplace the charging cable a friend may have one you can use.
I use Jackery Giant to recharge my iPhone 5. As the name includes: Giant. It is a powerful battery backup. I brought it along on a trip to San Diego on the first weekend. I would keep it in a backpack and run the iPhone charge/sync cable to my backpack side pocket.
Charging speed is very good. I get from about 10%-100% in 90 minutes. Thats 1% per minute which is the same as I get when connected to an AC outlet. About 2.5 full charges before it flashes one light on the charge indicator LED. It's likely that it could go another round but I never need more then two charges in one day even when navigating with location services all day.
One way that I have been using it lately is by tossing it in my pocket and working in the yard while recharging the iPhone 5. I have a Lightning to USB Cable (2 m) that I thread thru my belt loops around my waist. In one pocket is the Jackery Giant. In the other pocket is a charging iPhone 5 with length to spare. Usually I am listening to podcasts on the go.
Thats why I prefer carrying the Jackery Giant and choose not to set my phone on a charger. I have not had any complaints about the size or weight. It is now June 2014 and I continue to use the product.