Does what it is supposed to, I've tried 10 or so keyboards from major manufacturers and generics, they all worked. That's it really its a keylogger it does keylogger stuff. Two minor niggles, follow the manual steps carefully to set the time and date, rather fiddly and the password is only six digits, letters only, long, the PS2 from the same company has a more realistic eight digits.
To get it to work, make sure that the target system knows the keyboard first, don't just plug a new keyboard into a system with the logger attached it won't work. also, standard USB audit software doesn't see it but tools designed to scan for key loggers does see it. It isn't invisible to remote scanning, just hard to see but I beleive that is a limitation of USB not the logger.