I have used uber at Disney and it was generally great (and cheap). I would leave lots of extra time to get to the Port though. I take ubers a lot and have had many drivers get lost, not know where to pick me up, etc, so that it added a good 10 minute wait time. At Port Orleans, it took an uber driver 15 minutes to get there and I had been quoted 6 minutes.
You can price out the trip on the uber estimates website. I agree with the above poster that it might be close to the same price to arrange for a car if you plan to order an Uber XL and you avoid the worry of waiting for the uber.