I've mastered several of my songs with this tool and it is amazing. There are reference files (over 200) that will master your song to that genre.
It can also master individual tracks, vocal, guitar, bass and there are reference files for this also. You can also load up a file for just EQ or compression, bounce it against a reference file, and it will give suggestions for EQ and compression that you can then apply through whatever other tool you have. It will produce a printable reference file that you can use. Try it out and let me know what you think. :D