should i go with this extended battery or anker ?

its called Anpower.. the only thing that pushes me away from the Anker 6440 MAH battery is the back cover being black (and the ZL battery is too heavy for me, i owned it for my s5 and its a brick..even though performance is amazing but it is too heavy)
, i want to have a white one on my black note 4 , here is the link

http://www.amazon.com/DEALPEAK-Samsu...tended+battery

also, upon getting any extended battery , is fast charging damaging for the battery or not ?