Less than 24 hours after getting my 650
I'm already spending time troubleshooting the various problems it has with sync via the Reader Library software, which should provide the same kind of no-hassles sync experience as, say, iTunes does with its devices. But having already encountered the multiple-copies bug several times and ultimately having had to format the reader's memory and start again, I have observed something that might explain things. Maybe.
The multiple-copies thing started after the first few syncs went flawlessly and I'd shut down the Library software, waited for "do not disconnect" to vanish and unplugged the 650. A while later I wanted to add some more books, so I added them to my library, reconnected the 650 and let sync start. It failed on the first book, hanging for some time and then throwing up an error that the device was inaccessible. Thing is, the device WAS accessible, and I could see it in Windows and in the Library software just fine. Shut down Library, unplugged, re-plugged into a different USB port, synced again, and got the duplicates... and then another "device can't be accessed" error.
Then after connecting it a third time, Windows 7 threw up a warning that there were errors on the volume "READER" and insisted I do a scan. I did, and it found truncated database files and other file system errors. This is the point where I reformatted again - but before doing so, I checked the write-caching setting for the 650's drives. And both were set to "Optimise for performance", a setting usually NOT used for removable media because it delays writes to the drives. But trying to change it to "Optimise for quick removal" failed - Windows 7 said the device was hard-locked to its delayed-write setting.
What this means in plain English is that if you want to avoid corrupting the reader's file system, you MUST do a "Safely Remove Hardware" (from the system tray in win7) on both the reader's active drives. Since doing that I have had zero problems, though I have more testing to do with the Library software tonight.
This is incredibly bad design for a removable user-writeable disk device. Sony needs to fix this ASAP. As an example, even less frequently removed drives such as my Western Digital MyBook automatically set themselves to "Quick removal", since WD knows all too well that the alternative is data loss.