I ordered this after reading numerous bad reviews of the cheaper products, and Yamaha being a very trusted name in the music world I decided to go for it; and I am glad I did! I am avid organist, and have installed both Miditzer and Hauptwerk (Paramount 310 Theatre Organ), both of which work great with the UX-16. Polyphony is fantastic, little if any latency, and runs very well with both Windows XP (pro 32 bit on a low-spec laptop) and Windows 7 (64 bit). The cables are nice and long so no issues with length, and the unit looks nicely made and tough enough to take being slung into a flight case or swung about a bit by gigging musicians in need of a trusty Midi interface, so no worries there either.
It is advised to run the UX-16's driver/utility disk (provided with the UX-16) BEFORE plugging the UX-16 into the USB port, although the drivers for Windows 7 were not on the disk, but a link was provided to download the latest drivers, and everything went smooth as silk and worked perfectly. Remember also, as already stated here, to plug the OUT cable of the UX-16 into the IN port of your Keyboard/Organ/Etc, and the IN cable of the UX-16 to the OUT port of the instrument you're using. Opposites attract...
All in all a great product and ideal for budding home-musicians and gigging pros alike.