I have documented the freezing screen issue in the past. Well after getting it back in November from the local Pioneer repair shop all appeared to be fine. It also coincided with temperatures here in Texas typically lower than 75f. As soon as it got hot in March, it started freezing again. The local shop tried an update, it did not fix the problem. They suggested contacting pioneer. I did and they are swapping it out for the 8500.
My unit had been in the shop for a couple of months in the ten or so I owned it. There are cases of others with screens freezing, and I cannot help but wonder it was a bad batch made. I had three crap out from the same seller on Amazon, and I shall never buy a head unit from this place again. The first one was returned, the second I attempted to take to the local repair shop only to find out it had a bogus serial number, the third one was fine. I have spent over $70 in returning these units!
My honest opinion is when it works it is an amazing unit, when it freezes rather a pain to cycle the ignition to clear it, dangerous too!
The good news is I own a droid phone, so finally, finally I shall be able to use it on the 8500.