I'm so glad to see at least SOME interest in this sonata!
It really is a gorgeous piece if you're into post-serialist and avant-garde serialist music. It's almost Debussian in how it uses timbre and color; more akin to say, Consollation from Boulez's Troisieme Sonate pour Piano than the technical and harsh Premiere or Deuxieme Sonatas. The Barraque Sonate has a very mellow sound; much more accessible than most of his peers like Stockhausen and Babbitt. As far as getting a recording I can upload the one I have in a couple days if you'd like, or you can buy it off of Amazon. There is one really bad recording of it but I don't remember the pianist >< I think the bad one was recorded by one of the Sorabji virtuosos. Just make sure you don't buy that one XD