I have a Yamaha YSP1000 that is probably 3-4 years old by now, and I am thinking of upgrading it to a YSP4100 or YSP5100. So my simple question is how would you rate the YSP4100 and YSP5100 against the old YSP1000? Or perhaps put in another way, has the technology evolved enough so that you will be able to hear the difference between them assuming the rest of the factors are the same (same room etc)? I'm mainly interested in surround sound here, or at least TV/Movie sound.
