Steve, summed it up the best. Nothing remains the same, but both events are worth the travel. I've missed 3 Hershey's since 1967. And I worked for Carlisle as their Marketing Director for close to 9 years for most of the 1980's going to California in 1990, and I had not missed a year prior to that from when the Miller's created the place in 1974 in responce to AACA restrictions prior.
I missed going to Carlisle for about 10 years while I was in California having only enough time to make it to Hershey, always my first priority on my antique car travel budget. I think I went back sometime in the very late 1990's and told a couple friends I was going, I got the old "it isn the same, only sock vendors, no car stuff, greedy owners drove out the car guys" . The same critique I always heard for years prior to going away. Anyway, my point is...when I did go I found what was the same far out weighed what was not, and Carlisle today is still a mecca for car guys of a later model bent, and Hershey a little older demographic car group. Guess what? Still plenty to see and do for call, both shows are great. Hershey can't be truly replaced even right down the road, and Carlisle more commerically run makes the experience more pleasant, with less rules. So, these days, I never miss a Spring Carlise or a Fall Hershey, filling as I can find time with some of Carlisle's specialty shows, like Ford, and MoPar, and their new auction series. The last two years much to my wife's chagrin, I've made it to both Fall Carlisle and Hershey, while I am still young enough to walk it all without the aid of a "power chair/scooter".