I had a Mathews Creed that I bought new when it came out when I was 16 or so. 25 now & still have that bow but found too good of a deal to pass up on a new V3 earlier this year. I was in the boat of the specs not being different enough to justify spending the extra money on a new bow that didn't seem like much of an upgrade. On paper the V3 isn't much different than my Creed. I figured if it was pretty similar when I shot it I would just sell the V3 for a profit.
For me though the real difference is in shooting the bow. The V3 feels so much different when shooting than the Creed. Smoother, quieter, more solid back wall, steadier on target & just overall more comfortable to shoot. I've shot some other newer bows & I get the same feeling from most of them compared to the older ones.
I'm not trying to say Mathews is the only way to go but in general the newer bows definitely are an upgrade over the older ones. From year to year they may not change much but after 5-8 years or so there is a significantly noticeable difference. You've just got to go try out different bows & decide what price point you are comfortable with/how long you want to keep a bow before upgrading.