I will confess to being a bit dubious about this product at first. There are an awful lot of very expensive midi converters on the market; surely there must be a reason for this? Seemingly not. Plugged it straight into the piano at one end (little midi lights come on to tell me I got it right, which is handy as it is a common error to get the midi cables the wrong way round), plug it into the PC at the other (more little lights to guide you) and my PC (windows 7, if that helps anyone) wakes up and goes "ooh, looks like we need some drivers". So off it romped, found some drivers, and we were away. All without intervention from me.
My music composition software (Sonar) spotted the device straight away and that was that. No noticeable latency (any there might be can be squarely attributed to my sound card) and it's been working reliably ever since. Bingo.
NB since I wrote this review I've replaced my sound card, and this confirmed that this product was not the source of the latency. 6 Months on, its still working well.