I did notice in the youtube discussion that people are all bout the "weird" voice, and then I noticed that I'm actually reading youtube discussions. I just feel that a band sound should be recognizable, and not common to all others, and that's what La Roux achieved.
Though I think your use of the word "unconventional" was in its place, I don't think you need to go through a dictionary or a thesaurus to check for a better word.
