I have had the 505 for over a year now and love it. I sure wouldn't trade it for the 300 or the 600. I was lucky and it is perfect for me.
I tried to get one of the demo 505s at a local Target and they said it had to go back to Sony.
There have been members that have purchased the demo units. Sometimes it has to be taken out of the demo mode. This is the thread I marked for
demo mode units. Make sure you use the most current firmware.
Since you have been around the forums, you have probably seen the extras for the 505. You can check out
this thread by daffy4u, as she is experimenting with the 505 and customizing it (her Grand Experiment

).