Differences between the AVH-3500BHS, 4500BT, 5500BHS and 8500BHS's
3500BHS - smaller 6.1" fixed screen, includes HD radio, blue tooth including blue tooth streaming and Pandora over blue tooth. 1 rear USB port with extension cable, 2 volt pre-amp outputs
4500BT - larger 7" screen (motorized) , does not include HD radio, blue tooth including blue tooth streaming and Pandora over blue tooth. 1 rear USB port with extension cable, 4 volt pre-amp outputs
5500BHS -larger 7" screen (motorized) , does include HD radio, blue tooth including blue tooth streaming and Pandora over blue tooth. 1 rear USB port with extension cable, 4 volt pre-amp outputs
8500BHS - larger 7" screen (motorized) , does include HD radio, blue tooth including blue tooth streaming and Pandora over blue tooth. 2 rear USB ports with extension cable plus front SD card slot located behind the screen plus removable screen for anti-theft, 4 volt pre-amp outputs
My experience is with the 4400 and 8400 from 2012 and there is a difference between the two as far as USB music goes. The 8400 will write an index file to the storage device but the 4400 will not, this makes playing music over the USB input faster (MUCH) to initialize with the 8400 vs. the 4400. I believe this difference wil probably carryover to the 2013 units but I'm not sure. It makes no difference for Ipods, just for USB memory sticks or Androids if you mount them as a drive over the USM cable which doesn't work with all adnroids...