I rented at each of the parks. We had planned breaks each day. The only day we took one was the first day - due to the fact that my 4 year old son was falling asleep in the stroller each day!! The hard plastic ones we just rolled up a sweatshirt and put a towel under him. He didn't complain. LOL The strollers at MK, AK are hard plastic and don't really recline. My son was 41 inches he would sit in it with his legs stretched out in front of him, and had plenty of head room, and plenty of leg room. The strollers at MGM and Epcot are jogging strollers that always recline about 25%, soft sided. He was sleeping 1 1/2 to 2 hours in them, so they couldn't have been that uncomfortable. I believe somewhere on this site is pictures of the strollers. We never had trouble standing in lines to rent, or return. Even at park closing.
I have a jogging stroller at home so it was out of the question to bring that with us on the plane, too big, and too expensive to get lost or stolen. But I honestly didn't notice many people having their own strollers there. Best of luck on what you decide. Janis