I think it's just like computers and golf equipment. Every year something new comes out better than the year before. The marketers convince us that the one we have now won't cut it anymore. Sadly, most people, would rather chase thier tales buying equipment that makes it easier rather than improve their skills. There is no doubt in my mind that the new expensive bows are better, but I don't know that I need them. My honest opinion is that no way on this planet is a bow worth $600 - $1000.
The flip side to my opinion is the 3D shooter who competes and this is his main "thaing". For this person, they know what they need to improve thier skills and will spend the dough. For the average hunter like myself, it's hard to justify that kind of money. I believe in buying good quality equipment that will last and make clean ethical kills. I believe ANY of the bows produced today, regardless of cost, will meet that criteria.