As you may have picked up, there's no love lost between the author of the original RTEncoder, and the Java lookalike. There were some tales going around that the two weren't 100% compatible; although I don't know how true they are, or whether they've been fixed, that has probably tended to sway most people (i.e. Windows users) to the official version. On the other hand, as far as I know Mac users have no other choice when faced with an RTE encoded file, so I suppose you could say that it was widely used among Maccers. ;)