I've noticed that the main difference between Hoboken/60s Starfires vs Westerly 70s and up are that they are have a slightly thinner body depth and lighter build. I think newer SFs up through the 2000s have slightly more bulk to them and feel more solid. As a result, I feel they resonate differently -- not better or worse -- just differently. I prefer the lighter builds of the Hoboken years, but I've played many fine SFs from Westerly that sound and feel great.
And although Guild is known for having very consistent neck profiles, especially during the Westerly years, the earlier year examples commonly have slightly thinner neck profiles.
There are many other marked differences from electronics, finish, hardware, et al., so you may want to try examples from both eras to see what you prefer. For more in-depth info, check out GAD's excellent and thorough reviews of SFs from three eras. There's a link to his blog in his signature.