It is, but, from playing it, its very hit and miss...
Its new version is buggy so shouldn't really be used.
I've been asked to download the last revision and a mod called RF 2.0 from the forums:
The only difference from the old to the new really is the fact it hasn't got Hammer On's and Off's, but those are buggy on the new version to the extent where its almost unplayable.
The old version works slightly better, but its too accurate in the sense that if you miss it by even a milisecond or something, you don't get the note.
They really need to sort that out to make it more playable.