Well I have a few CDs of the Viennese school - Berg, Webern and Schonberg and their early attempts at serial music and 12-tone rows. And it can sound "bleedin' awful" - but I do like the Berg Violin Concerto - although I think this has other stuff in it as well - so it might be the contrast and tension/release that makes it OK - whereas 'unrelieved' atonality on this scale is pretty unbearable!! Messiaen is also supposed to use this method and I love his music - although again, he throws in loads of other methods of composition as well, so it is a case of : in context it sounds good, but if something is just based on one 12-tone row it sounds painful.....?
Well it doesn't have to - but I think you will find that a lot do and if you have to re-set your machine each time - then you might as well throw it away - even a 12-Bar Blues changes key!!