I bought the TomTom one, and it charged, but didn't work with GPS (and yeah, I used the helper app they say to use)... and online some say it works, some say it doesn't - not ideal for reliability. I exchanged it twice just to make sure. I even contacted Tom Tom and they said it's working for some... lol, how's that for reliability... "working for some" ... lol. Are there any other makers out there that make the windshield mount that's iPhone 4 compatible yet, or should I just keep holding off till they come out with a Tom Tom version? Seems like the iPhone 4's been out long enough that something would be available. The Navigon and TomTom software is great, but I want the extra reliability, windshield mount, and charging capability that comes with an actual kit.