I'm on my second one of these RoadWarrior chargers/transmitters, and I have to say I'm disappointed.
In theory, and for the first few weeks, they work great, although one could use a little more traverse on the clamping mechanism to better accommodate the 6 Plus in a case, and a longer gooseneck model would also be nice for some cars. The transmitter is good, and it's very convenient.
But after a few weeks, a message consistently begins to come up on the phone "This Accessory May Not Be Supported", and it fails to charge. At the same time, the base seems to begin to come loose.
The transmitter continues to work fine, but the inability to charge the phone makes this a deal breaker.
Nice idea, good form factor, good transmitter, but needs some work before it's ready.
If the next version of this were more robust, I'd eagerly give it a 5-star rating, but I regret that I can only give the current version 2 stars.