I kinds skimmed through this thread, so forgive me if someone already suggested this, but I like to NOT buy Park Hoppers. That does not mean I won't use Park Hoppers, it simply means I will add them (for the same $52.00) when I actually need them.
If you decide you don't want to hop, you saved yourself the money. If you decide the park is to crowded, or you'd rather be elsewhere simply go to any ticket booth and upgrade.
Furthermore, it just depends on how you do your vacation. For onsite guests it's nice to start in the EMH early park and then transfer in the afternoon to usually a late night park like Epcot. This gives you a very full day. The time lost tranferring parks is gained with the extra time you get going to a late park. On shorter trips, it's a good stradegy to do it this way. You get the most hours at the parks this way.
If you like taking breaks away from the parks for a swim or nap, etc. then park hopping does give you the option of whatever park you feel like doing after your break. You haven't lost park time transferring; since, you are going away from the park, anyway. It gives you more chance to see MK fireworks and the night parade, as well as, Fantasmic.
On the flip side I think it's more stressful to park hop. I like staying in the same park all day. My mind is already in the mode of a certain park; so, I'm not rethinking it all midday. As long as, you schedule any special activities like the parades and F/W, etc. then you won't miss anything by not park hopping.
I like saving the money, too by not park hopping. I'll go to a fancier restaurant one night or buy that extra souvenir, etc. with the money saved from not doing it. This makes me happier then doing park hopping.
I've been over 30 times and there was a time I thought park hopping was the way to go, but no more; unless, it's a 4 day trip or less. We go for at least a week and sometimes two weeks, now; so, there's no park hopping for us.