I will qualify my response because I am certainly no expert on this battery but I will say that charging time definitely seems to be longer because of the battery's capacity. In another thread, in fact, there is discussion about the need for a 3.0 USB hub to charge the phone. I can support this, because my phone will not charge from a 2.0 USB connection - it barely holds its own when connected via usb.
I have had my phone on the car charger while running GPS and listening to a book and it seems to do fine. Of course there can always be other factors that might impact your battery while on the charger (like searching for 4g, 3g signals, etc.).
Hopefully others who are more knowledgeable than me will chime in. I can only relate my own experience.