Whilst I have heard of the Apple battery charger, it has recently come to my attention due to a staff request for one at work.
I have heard on the TWIT podcasts that the batteries included with the Apple battery charger are actually the same chemical make-up as the Sanyo Eneloop batteries. These batteries can retain 80 percent of their charged capacity and potentially last for up to 10 years of service life.
Whilst people could just go out and buy any rechargeable batteries I think it is good there is now an option for those who will only buy products branded with a fruity label.