I haven't seen the Tarkovsky version yet but I really enjoyed the Soderbergh one; it didn't seem to concerned with being arty or a faithful remake, it just told its story in the way that Soderbergh generally does.  It's gorgeously photographed and deals with some very interesting issues, the only drawback is that Clooney was a bit too flat in the lead role.  Natascha McElhone was marvelous and very hypnotic.  Don't ask me, though, because my friend and I were the only ones left in the theatre by the time it was over and even she was sleeping!