I haven't used Uber in Orlando personally (someone else paid for it), but I use it all the time here in New England.
Here are a few facts:
Uber is often cheaper than cabs.
It's local residents trying to make some extra cash driving people around. (So a Miami uber driver can't visit Orlando and make a few extra bucks while there - they have to apply for that region).
Uber can't typically pick you up inside the parks and definitely not at the cab/bus stands. Disney charges them for parking. (My friend missed a flight because he didn't realize this and wondered why it was taking a driver so long to pick him and his gf up from MK..he gave up and took a cab.)
However, they CAN drop you off inside the parking lots for the parks if you're staying at a Disney resort. This is because you get free parking by staying at a resort or have an AP. The uber driver will have to scan your magic band to gain access. (This should mean that uber drivers can occasionally pick up people inside the park, but I'm really not sure on that.)
Uber can definitely pick you up at your hotel or resort and take you to another resort or Downtown Disney (it's only when they charge for parking is it a fuzzy area).
Uber can pick you up from your hotel/DD and bring you to other Orlando attractions such as Sea World,
Lego Land, and Universal Studios.
In certain vehicles, you can link your own music via spotify for your ride. You might drive your driver crazy with Let It Go on repeat, but your kids might enjoy it.
Some Uber drivers include water bottles in their cars (take the bottle into the park to stay hydrated!)
Uber can be hit or miss - I've had some drivers really concentrating on service and making sure you have a fantastic ride, and I've had a couple experiences with a sketchy, old, smelly car and odd personalities.
Uber has been used for airport pickup though I have not personally used it for Orlando. Another trick you can try is go to the departures drop off to request an Uber if they don't allow personal cars at arrivals.
If anyone will be trying Uber for the first time in Disney/Orlando (or anywhere), you can use the following code for your first ride free (up to $20): kristien9