If you pair up the first five floyd and mars volta LPs, I think mars volta clearly wins. beyond that I can't really say, but I think they have shown they are a more evolved group, their albums are denser and have a wide range of influences in their sound, including punk and ethnic music.... IMO they have had three great LPs (deloused, frances, bedlam) in only five years of existence, and a couple decent ones. but I do have a feeling Volta's best work might be behind them, while floyd kept getting better at that stage. I was disapointed with octahedron, I am all for bands shifting it up but octahedron felt like a throwaway