It's not the fastest for sure, but I'm still testing. My plan is I have a dual port (link) with the adaptive charging port open so I can connect a usb cord to my phone for fast charging if I really need it. Haven't tested if the port makes a difference in wireless charging yet. I haven't used it a ton as I'm still waiting for the low profile cord but just today I drove around for about 20 minutes with the GPS running and it wirelessly charging and gained about 4%. Not a lot but at least I'm not losing anything.

Edit: Oh, and it was at 64% saying an hour till fully charged, not sure how accurate the estimate is