We have done both with a large group (7 or more) before.
Our drive is around 13 hours. With stops for meals and bathroom breaks, it ends up being more like 15 or 16 hours, so we typically do it in two days, and try to plan in some fun short stops to break up the drive about every two hours. For instance, when the kids were little, we might pack a picnic lunch and then stop at a nice park I found ahead of time to eat. Let the kids run around and play on the playground for a few minutes, walk the trails, etc.
But now that everything has gotten so expenisve, we are finding it is cheaper to fly after factoring in hotel, gas, and food both days. My kids are grown now, though, so we don't have as many people going at once anymore. Not sure how tickets for 8 would compare to expenses of driving, but if it is the same or cheaper to fly, I'd do that for sure. I don't see any reason to make such a long drive, unless you all just love road trips.
The times we have flown, we either used ME or a private car service that allowed us a grocery stop which worked great. Although, now with all the grocery stores that offer delivery over the internet maybe not a as useful, not sure. Always used Tony, but think last I checked, he has retired, so don't have a recommendation.
I have also used Uber my last two trips down to Orlando. This was at Universal, not Disney, and I wasn't using Uber for transportation to the parks, just around Orlando, but it worked great. Never had any issues getting a car when or where I wanted to go all times of the day and night. It was usually $20 a trip, except MCO to resort which was $40. Not sure about Ubering with a large group, though.
I'm not a big fan of driving, especially in Orlando traffic, so we tend to take Disney / Universal transportation once we are there even if we have a car. As long as you research what's available, how to get from A to B, and know realistically how long it is going to take, it's not bad. Maybe had a problem with a bus not coming once or twice in years of trips.
Just make sure to factor in time to walk to the bus stop, wait for the bus, the bus ride length, time to walk from the bus stop to the park entrance, go through security, and then walk to wherever you are going inside the park. I think this is where people get tripped up. They say, "It's a 30 minute bus ride." They have a 4:00 reservation, so in their mind they think, "Oh, I should leave at 3:30 or maybe 3:15". They don't factor in the 15 minute walk to bus, the 15 minute wait for bus, the 5 minute walk to security, another 5 through security, 15 to walk through the park to the restaurant. There's probably 45 minutes to an hour of extra walking / waiting time in there that they don't think about. Then, they blame Disney Transportation for not getting them there on time when it is really their own fault they left the room at the wrong time. Just do your research on how long you need to give yourself, and you shouldn't have too much trouble with the buses.
As far as car rentals, in November, I was in Orlando for work, and we needed a car rental that seated 8 or 9 with the extended cab for luggage. There are very few of these cars available. I had a hard time finding any rental companies with them. I finally found that Alamo offered a few, and Alamo also has the option to check in online ahead of time and go straight to the car. It worked great. I would definitely recommend that again. You might want to price out what renting a car for the whole trip would be verses booking two car service trips to and from. It might end up close to the same. Then, you'd have it, just in case. We've had trips where we needed to go to a doctor or pharmacy and a car was nice. Also nice to have a car if you are planning any non-Disney activities like the beach, Universal, Sea World, Legoland, the orange groves, Tampa, or Kennedy Space Center.
Also, not sure if you are staying in Kidani, but be aware those rooms can be a long walk to the bus stop. Our walk was around 15 to 20 minutes when we stayed there in a villa, and despite asking for close to bus stop because we had someone on crutches, we did not get it. There are so few rooms close to the bus stop, don't plan on getting one. If you have a car, however, it will be close, right outside the room.
In summary, about 50% of our trips, we have had a car, but we basically use it to get groceries at the begining, for emergency medical issues, and for vistiting non-Disney attractions. Otherwise, while at Disney or Universal, we park it, and it never moves again the entire trip. We use theme park transportation for getting everywhere around the parks and never had any issues with that more than once or twice with planning.
