I wanted to write in more detail, but life kind of swept me, so here's my short impressions from a comparison between the 2009 and 2010 version of the Optimum edit:

Overall, I think the 2010 sounds just slightly better - more "relaxed", not so noisy and bombastic. There's more depth to the sound, which makes it more clear, even if some sections are slightly fainter than the previous. 2009 has louder overall feel, as if all of the instruments are up front. The livelier tracks sound great, but it's a bit too much for me.

I still like them both. There's seem to be new version, however.. maybe I should wait until the actual final, definitive one? :p