Pretty much ever since Disney invented the "Park Hopper" (you can hop from park to park and visit more than one park in one day), our family has hopped the parks. Since we visited the parks frequently (averaging once a year), we would buy a 10-day park hopper ticket, no expiration, and use a couple days on the tickets each trip usually seeing two parks in one day. We knew which rides to hit, which to skip, and we made the best possible use of our time bringing in snacks, drinks and lunch (so we didn't have to break for food). They were long, packed days, but we saw a lot and could use the other days of our vacation week to relax or visit other Orlando attractions.
When we visited Disney in August, 2013, we purchased 5-day, non-hopper tickets. (All our days on the non-expiration tickets had been used.) The "hoppers” were just too expensive for a family of four, now all paying the adult price. (Our kids were now 13 and 11.) And we knew that we were unlikely to return to Disney in 2014, so we didn’t go with the non-expiration option. We purchased the tickets through Undercover Tourist where a 5-day ticket was actually cheaper than a 4-day one. With a non-hopper ticket, our plan was to do one day at each park, taking our time, not killing ourselves, and then choose a park to return to for a little bit on day five. (Note that as of 2015, the no-expiration Disney ticket option has been eliminated.)
The verdict on the non-park hopper? It was a mixed bag. In some respects, old habits die hard. We initially still had the "do as much as you can, as quickly as you can" mentality and closed down the parks the first three days -- we were there when the parks opened and there when they closed. Not a big deal at Animal Kingdom which keeps shorter hours anyway, but two straight days of 9 to 9 at Magic Kingdom & EPCOT had us pooped. Still, even on those long days once we hit the "big ticket" rides, we were able to slow it down, relax and enjoy other shows and attractions in the park that we had not seen in quite some time. For some attractions, we remembered why we had been skipping them (Rafiki's Planet Watch in Animal Kingdom for example) while others were pleasant surprises (Flights of Wonder show in Animal Kingdom). We did bring some snacks and drinks into the park on some days, but traveled relatively light, took time for nice meals (Tappan Edo in EPCOT, Be our Guest in the Magic Kingdom, Sci Fi Drive-in at Hollywood Studios) and snapped plenty of pictures -- especially our kids who were posting everything on Instagram. And after becoming pooped at the 3-day mark, we reduced our time in the parks too -- leaving Hollywood Studios after a late lunch to go back to the hotel and swim, half of us returning for Fantasmic and the other half just hanging at the hotel. And the 5th day was a nice leisurely return to Magic Kingdom.
So what would we recommend? All in all, if you have the time in your vacation to really enjoy each park, instead of rushing through them, it really is nice and a hopper isn’t necessary in my opinion. You can enjoy the amenities, the details that you miss when you're running around, and be more relaxed during your visit. Especially if you are new to Disney or haven’t been there in a few years, take your time, save your money and skip the hopping.
On the other hand, we don't always have 4 or 5 full days to enjoy the parks and even if we did, sometimes you just want to hit the "high points" and see a couple parks in one day. Or, if you're a frequent Disney visitor you may not want to see everything in all the parks. So in those cases, a park hopper may be a better use of your time. Also, if you’re traveling with extended family or older teens, a hopper gives you more flexibility to explore the parks and meet up throughout the day in different locations. With bigger groups, it is unlikely that everyone is going to want to see the same things or be in the same parks at the same time.
If given a choice in the future, will we hop again? That's a question I still ponder. For us, it will depend on the length of our vacation and the price. If annual ticket price increases continue at the rate they have been going, I think non-hoppers will likely be our choice.