If you charge the battery at greater than 1C (the battery's capacity, IOW), you won't benefit, the battery manufacturers will, since you'll be replacing the battery more often. Quick charging is an advertising gimmick, not a technically good way to not have to replace your battery often. (Or, to put it in simple words - the faster the battery charges, the more often you're going to be replacing it.)
Yes its works... I'm using it right now!
Are you noticing any odd effects? Have you tried surfing or using some apps while charging? I ask because when using mine (off-brand Qualcomm 2.0 from Amazon) the phone will often freeze or refuse to respond. When I take it off charger, all is well.
Is it an off brand or knock off? If it's a knock off, then that could be the culprit. If suggest sticking with official or third party name brand chargers for replacement.