@BuSaBumNim
FIrst off it seems likely there is an issue with charging issue, not that it takes longer (that's just physics). Nobody is arguing that. There are people who have defective units (it's an unfortunate part of the production process, it happens). You need to understand that Apple uses a smart charge algorthm that is designed to give the battery longer life. The charge "curve" can by all accounts be managed in software. So the genius may be close in her assessment. Apple products don't work like those plastic knock-offs. Those third party devices charge at full rate at all times. They slam the batteries and make them have a shorter life.
Before you start telling people to buy things and possibly waste their money consider a couple things. The devices are less than a week old and the batteries are not yet broken in. Talk to a Prius owner that bought the car new (of which I'm one) and they will tell you that you MUST "break in" the batteries correctly. Once the batteries "break in" the gas mileage goes up considerably because the batteries are working better.
Another thing to consider is that this third party charger my cirvumvent Apple's charging technology and you may be damaging your iPad batteries. I can't be certain of this, but it would be best to speak with Apple to be sure. Be careful of these internet experts.
I agree with DaveBLondon. It's possible you have a defective charging unit. Wouldn't it be cheaper to get a replacement from Apple first a test it before spending your own money?
I'm patiently waiting for it may be a week or two (possibly a little longer) because it takes time to fix test things like this. I know this because I do this for a living and I know it takes time to do it right.
Apple has some very good web pages dedicated to their battery technology if you're interested. They are very well written and they are not written in Engineer-eze. I encourage everyone to read these to get the most out of their devices. Here are a couple links.
http://www.apple.com/batteries/
http://www.apple.com/batteries/iphone.html