We just got back and here was my experience with a large group:
We picked a hotel near the airport because I anticipated one or more flights being delayed and it's soooo much easier to coordinate with an airport hotel shuttle than a third party transportation company. We did the Fairfield Inn MCO, they were GREAT, loved it, big pool, nice rooms, and lots of options for dinner (that they will shuttle you to, or you can walk, as there are tons of options less than a mile away and there are sidewalks the whole distance). So that part was super smooth.
The trip to the port stressed me as follows: I found out that morning that our shuttle was going to be an hour after our original pickup quote - we were quoted 10:45-11am and the front desk said they were scheduled to arrive at 11:45am. I called both Go Port Canaveral and the transport company because I hadn't been thrilled with the time to begin with, so later was a problem. I have no idea if it helped, but the bus ended up showing up at 11:07, and when the driver realized how many people/bags there were, he radioed for another bus, which arrived as soon as our bags were all loaded. The trip ended up being really fast, he dropped us off first, and we were able to walk through the terminal and right onto the ship (except for an Incident in the terminal with one of our group, my heart stopped I swear, but on the plus side by the time her situation was resolved rooms were open and we were able to all eat together in Cabanas, so win?).
The return was very smooth, loaded up on a bus, waited a few minutes for it to arrive and a few more for it to fill up, and then dropped us off at the airport. Some stayed there and some used the return privileges at the hotel (called for the hotel shuttle to get brought back, spent the day at the pool and had lunch there). The boat cleared on the later side and we were still back to the hotel before 11am, even with all that.
A lot of my stress came from trying to herd 30 people different places, though, to be honest. It's not like I could have called a cab in an emergency! Overall, they did what I needed them to do, so I would absolutely do it again with a smaller group. Next big group trip I might roll the cost of the Disney shuttle into the upfront quote for my own stress reduction (just wish it stopped at the Disney hotels earlier, we like to get there early!).