Afaik, MultEQ XT32 can also apply more and more precise filters, which could help get the actual system response closer to Audyssey's target (versus lower implementations).
a bit technical Veegee but this explanation of sir Ivan is the best reason why I would go for the 3008 though older model compared to newer model 818, im sure sir Ivan would oblige if we ask some layman explanation of what more precise filter is all about
since the 3008 is cheaper compared to the 818 or 3009, you can enjoy high end features present in both the 818 and 3009 and a chance to save some money to get a better speaker set in the future. The 3008 used to cost 2K USD and above, Amazon price is very erratic, once a bargain comes along and you really like the item, grab it, I got my RC HT 180 before for close to 800 USD, after a while it became around 550 USD, after just a couple of moths or so, the HT RC180 went back to 800 plus USD, same thing for higher models, im sure the price of the 3008 right now may not be the same a few weeks or months from now.