Just back, rented 2 City GT's from Orlando Stroller for the week, we liked 2 singles as compared to a double.
We stayed on site at Beach Club, so WDW transport with a stroller was easy. We walk to Epcot, so stroller was great for that and great to have a stoller in Epcot at night so kids could sleep while we food and wined. We mostly walked to HS, but took boat once. It is a long walk, so stroller was great especially since it was basically a jogging stroller and rolled real easy, much better than the Umbrella Maclaren stroller we brought from home in the past, and infinitely better than a cheap umbrella stroller with too short handles. As for boats, we did not need to fold stroller on the boats, just park them open in the back of the boat.
For MK, we mostly would walk thru Epcot (and grabbed a drink on the way) from our hotel to the Monorail and took that to MK since we have annual passes and can park hop. On Monorail, you do not fold the stroller. For AK, Downtown Dis, and when we had to bus to MK, we had to fold the strollers. The rentals where easy to fold, the only issue is that you need to take the stuff out of the bottom of the stroller for it to fold. We found that having all the stuff in the bottom of the stroller in a bag made this process much easier, just pull the bag out, fold, and get on bus. Strollers were not too heavy, I could carry both no problem.
As for the strollers themselves. Very clean, very new, came with rain covers, had nice handle set up with adjustable handles, and a parent carrier thing mounted on the handles with 3 cupholder sized areas great for beverages, sunscreen, phone, sunglasses, etc... The storage on the bottom was relatively large and useful, however it was hard to take a bag out or put it into storage area with a kid sitting in the stroller, had to ask them to get up, bag could be accessed with a kid sitting in stroller just not taken out easily. large canopys on strollers, reclining seats, and kids often passed out in them.
Stoller rental was really really easy, booked online for a fraction of the price as in park rental, the rental company had dropped it off prior to our arrival and bellman brought it out while we checked in with only a simple sign out sheet to get it. Stroller rental company also sells bottled water, so we had 2 cases of that delivered with stroller, a huge money saver in parks. At check out, we simply rolled the strollers over to bellman, signed them in, and left, stroller rental people picked it up a few hours later.
So ridiculously easy and cheap. Definitely pay the extra $10 for the week to upgrade to the GT as the single front wheel is much better as are the adjustable handles. Folding the actual stroller is easy and taking it on the bus is easy, just make sure to have the storage area organized, if you just throw crap in there then you will have to organize it all when it is time to fold it up. Quality and ease of use is so much better than in park rentals. It is smaller, more maneuverable in crowds, easier to push, better cup holder area, and much better for sleeping children, and infinitely cleaner.
I would not do it any other way, just wish I had tried it sooner as last trip we used umbrella strollers which were a pain and had to be lugged with us on the plane.