It's a terrific example of world-building, isn't it? I've read them all and The Hienama and The Student of Khyme, which basically overlap or take place shortly after the first three books. Sometimes I ask myself what fascinates me so much about it. I guess the gender-bending, the sex magic, and the general complexity of the characterizations (nobody is all good or all bad), and also the continual striving of the characters to understand themselves and their world is addictive. Gorgeous young guys has nothing to do with it I am sure. If you ever want any recs of fanfiction I can give you some. I have one major favorite by Thevina, Maelstrom and Mage, which also has a terrific sequel. (She is actually in the processing of expanding and editing it for publication by Storm Constantine's Immanion Press. Storm takes fanfics and publishes them and then considers those stories part of the entire Wraeththu canon.) I love that an author is willing to encourage the creativity of fanfic and share her world like that.

P.S. I just realized that you said you bought the two published fanfics. Duh! Speed reader here, who misses things. Actually, I think Maelstrom and Mage is better than those.