I purchased this Epson Duplexer for my Epson Artisan 800 All-in-one inkjet printer over a year ago. Overall I have been extremely happy with it. I do a light volume of duplexing; maybe 10 to 20 sheets a month maximum.
-Easy to install
-Easy to use
-Works with the Epson drivers in Windows XP, Windows Vista and Windows 7 environments
-Has functioned without incident (i.e. no paper jams)
-None to date
-Adds about 3" to the rear of the my Artisan printer (this may not be an issue with other printers)
-Obviously adds a bit of time to duplex vs printing one sided since the printer must give the paper additional time to dry before it prints on the other side. On the plus side, duplexing does saves paper
-You will want to adjust both your drying time and ink density (from within the Epson drivers) if your duplexing is causing the paper to wrinkle (very easy to adjust).